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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: AmigaMance on June 10, 2007, 02:25:03 PM
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Can a CPU (68k, PPC603) become slower by the passing of time, if it suffers from mechanical (bumps) or thermal stress?
I'm not talking about the clock frequency, which will be always the same (i guess) but about the overall performance of that CPU.
Well, i warned you that this is a stupid question, so be gentle. :-D
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No. A CPU either works or doesn't work, there isn't a degradation in performance over time like with mechanical items.
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No
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I'm not sure about the PPC family but the 68K family should not be able to do this... on a 86x it's theoreticly possible as some of those CPU's have a downclock feature when they are experiencing overheating so if the CPU is damaged in a way that over time makes it more and more prone to overheat during normal usage or even idling then I think this would be a theoreticly possible phenomina.
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A few months ago I read an article at register.co.uk in which Intel stated that certain CPUs from certain production lines (call me Celeron) become 10% to 15% slower after 5 - 10 years. It's somekind of semiconductor third-age, they said.
And I am able to verify this.
My brother bought a 466 MHZ Celeron pc back in 2000. Unsirprisingly it's performance sucked. Only 900 marks on 3dMark 2000 right after a clean intallation of windows with the latest drivers for graphics and sound.
6 years later I was called to format the hard drive and reinstall windows 98 because (unsurprisingly again) the old setup got seriously messed up. Again win98 , same driver set, 3dmark 2000.... guess what.... 762 marks!
My brother will need another computer pretty soon
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Could you dig up link for that article?
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I highly doubt this happens... 99.9999% this is BS
also the celeron benchmark , is it valid? he used the EXACT same setup/driver combo ? everything SAME version as the first one? Any new progs running in the background now? it is very hard to believe this "degrading as time passes"
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Could you dig up link for that article?
I tried to. I wasn't able to find it. I'll try some more tomorrow.
@keropi
I used the exact same setup. Same harware (except for a newer better hard drive), EXACTLY the same drivers no other applications installed except for 3dMark 2000.
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There can be millions of reasons for system to slow down. I guess you could isolate it to CPU by trying known good identical replacement CPU?
Needless to say I'm a bit sceptical about this "CPU slows down by age" claim.
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@Van_M,
I'm going horribly OT here, cos I saw your tagline. not heard it yet, but I have heard the new single on Kerrang!Radio - sounded pretty good, but me missus thought he sounded a bit...errm...female ! I'll put that down to the crappy reception in me car at the time !
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I always felt that x86 CPU's tend to produce more heat and give lower performance after one-two years of heavy usage. But may be it is my expectataions that changes not the CPU itself.
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Cpu degradation? LOL!
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Why not test with RC5 to isolate CPU performance? :)
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@zombi
More like the cooler clogging up and/or failing.
More like games and apps requiring ever more crunch after couple of years.
:-)
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if it was true, my 15+ year old 386sx would be an XT by now :lol:
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keropi wrote:
if it was true, my 15+ year old 386sx would be an XT by now :lol:
And what would our Amigas have become? ;-)
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moto
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Lando wrote:
No. A CPU either works or doesn't work, there isn't a degradation in performance over time like with mechanical items.
A little bit more detail: there is wear internally in a microprocessor and one of the mechanisms is called electromigration, another is the degradation of the gate oxide that should act as an insulator but can break down (google is your friend !).
99% of the CPUs is externally clocked and you won't notice the wear out until the signals in the transistor can't reach the destination within the clock cycle. If that happens the CPU will abruptly fail or become unreliable. What can happen is that the power consumption goes up over time due to increased leakage currents in the transistors but most of the time this phenomenon degrades quite abrupt when it starts to be noticable.
greets,
Staf.
PS: I work here (http://www.imec.be) so I'm a little bit familiar with this material.
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Actual harddrive must be replace at least each 2 years if they are used 10h/days, after that they lost 50% of the speed output.
My source : my main pecee made in 2001 (Sisoft Sandra 2003/2004, chipset HTP Raid 370, swap+temp on an another HDD)
IBM 46 Gb : after 1 year, around 40% of perforce lost, then brokedown
Maxtor 20 Gb : after 3 years, around 50 % of perforce lost
Seagate 120 gb : after 1 year, around 20 % of perforce lost
Maxtor 300 Gb : after 1 year, around 10 % of perforce lost
Capacitors can be also problematic.
I changed all of them on a 2004 WinFast Nforce2 (they explosed one after one...), and some on 2003 MSi Nforce2. They now both work like a charm, and performances are back.
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@ Van_M
I remember that Register article. I also knew exaclty which date to search for it in the archive.
I went to 2007, and then April, and then Sunday 1st:
http://www.reghardware.co.uk/2007/04/01/cpu_time_dilation/
(sad that I remember it but that isn't the saddest example of my memory. I was in Ikea a few years ago and they had some mags on a table in a living room setup. One was CU Amiga, and had a picture of the 'New' A1200 on it. I knew then (but not now - I would guess at October/November 1992) which month and year it was - this was about 8 years after it was published!)
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A CPU running slower after some time is complete nonsense.
But:
- I had to downclock my Athlon XP 1700+ after ~5 years from 1866 to its nominal 1533 MHz - the system kept rebooting in spite of proper cooling. Probably a voltage raise would have removed the problems, but the board didn't allow for that and more voltage speeds up electromigration thus aging.
- I noticed my P4 Prescott at work was only throughputting 2 Mkeys/s in distributed.net's RC5-72 - the cooler was pretty clogged up. After a little bit of cleaning the noise was massively reduced and the speed was back up to ~7 Mkeys/s.
@CLS2086:
Have you defragmented your drives completely or formatted them prior to measuring?
My drives run 24/7 for years (usually 4-5) and I've never observed a significant (maybe barely measurable, but surely unnoticeable) decrease of speed (seek, throughput)...
They're not RAIDed however, in certain RAID modes you may see significant speed decreases when the drives are not spindle synchronized.
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I remember that Register article. I also knew exaclty which date to search for it in the archive.
I went to 2007, and then April, and then Sunday 1st:
http://www.reghardware.co.uk/2007/04/01/cpu_time_dilation/
Now, who am i suppose to believe? All you ignorants or Professor Asteio Artikolos?! My money on him. :lol:
@CLS2086
Actual harddrive must be replace at least each 2 years if they are used 10h/days, after that they lost 50% of the speed output.
My source : my main pecee made in 2001 (Sisoft Sandra 2003/2004, chipset HTP Raid 370, swap+temp on an another HDD)
IBM 46 Gb : after 1 year, around 40% of perforce lost, then brokedown
Maxtor 20 Gb : after 3 years, around 50 % of perforce lost
Seagate 120 gb : after 1 year, around 20 % of perforce lost
Maxtor 300 Gb : after 1 year, around 10 % of perforce lost
That's a very interesting post. Thanks, i did know about this. I have a 8GB IDE SeaGate in active use since... I don't even remember since when. I should have done some benchmarks when i first bought it so i could compare them with current benchmarks.
I can't say that it feels slower but this might be because i'm using the standard IDE port of my Amiga 1200, which is already slow.
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Stop........De-fraging a hard-drive is pointless. It will take hours and hours, and you will not notice the real world difference (apart from the old its supposed to be faster so it is effect). you will never gain back the time lost in de-fraging in a performance gain. And guess what as soon as you have de-fragged the drive it gets fragmented again.
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JJ wrote:
Stop........De-fraging a hard-drive is pointless. It will take hours and hours, and you will not notice the real world difference
The hard drive in my company laptop got to 70% fragmentation. I defragged it and it was significantly faster.
JJ wrote:
you will never gain back the time lost in de-fraging in a performance gain.
So do it overnight.
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moto
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Ok do it once every few years. Never bother doing as some suggest regurarly. It is a waste of time.
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Proper tools will do the defrag operation at scheduled times (such as during the lunchbreak).
Defragmenting is well worth it. It is not waste of time if you're not waiting for it to finish.
Fragmentation is especially bad with the paging file and NTFS Master File Table. If paging file (swap) is fragmented it will cause massive slowdowns to swapping operations. Similarily MFT fragmentation will reduce the overall performance of the filesystem, regardless if the files are fragmented or not.
Paging file can be defragmented with PageDefrag (http://www.microsoft.com/technet/sysinternals/FileAndDisk/PageDefrag.mspx)
MFT defrag is slightly more demanding task, the one tool I've found that does the job well is "Diskeeper".
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@CLS2086
I have to say I'm a bit sceptical about hard drives losing performance, either.
The only case I can think of is bad block remapping, which could in theory explain the slowdown. However, in practice I've never seen any performance loss.
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I think this has much more to do with the fact that over time we ask our CPUs to do an ever increasing load without changing the CPU's speed. Thus it seems to run slower when in fact we are just using a smaller slice of the processing speed pie.
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AmigaMance wrote:
Can a CPU (68k, PPC603) become slower by the passing of time, if it suffers from mechanical (bumps) or thermal stress?
I'm not talking about the clock frequency, which will be always the same (i guess) but about the overall performance of that CPU.
Well, i warned you that this is a stupid question, so be gentle. :-D
Nope, not possible.. It can however start calculating wrong if something becomes defect, which will most likely result in a unstable computer that crashes alot. I believe the cpu is the component in a pc that has the longest lifetime if used properly. Pretty much the only thing that is likely to kill your cpu, is heat, wrong voltage and overclocking it way up.
Actually i have noticed the opposite of your question. I found that a cpu clock lower when it is new, while after a few years i seem to be able to overclock it higher than when it was new.
One example was my old p1 133.. I first could only overclock it to 166mhz without stability issues. At 180mhz it would either crash at boot or soon after. Then later after running it at 166mhz for some time i could bump it up to 180mhz and after staying there for a while i could bump it up to 200mhz using the same exact components. It ran perfectly stable at 200mhz for years, even running seti@home 24/7 and would even nearly boot at 220mhz.
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6 years later I was called to format the hard drive and reinstall windows 98 because (unsurprisingly again) the old setup got seriously messed up. Again win98 , same driver set, 3dmark 2000.... guess what.... 762 marks!
Could be something simple as a missing or different version of the chipset drivers. There is just no way a cpu can get slower like that. The only way it could get slower, is if the speed was throttled down by bios due to overheating.
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@Piru
Thanks for the link to the pagefile defragger cause we all know that a fragmented pagefile does cause a real world performance hit and windows defragger does not defrag the pagefile as it is in use when the defragger is running.
Schedule to run in lunchbreak????
You must have a small hardrive or a really long lunchbreak :lol: Wonder how long it would take to defrag my more or less full 250gig sata HDD. Im guessing awhile
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Actual harddrive must be replace at least each 2 years if they are used 10h/days, after that they lost 50% of the speed output.
That also sounds like bull*it to me..
I have a old seagate 10gig from 1998, which has been running 24/7 since that time and still runs in my server today. The performance tests i did earlier this year shows that it still gives around the same performance today. Saying that it will be 50% slower after 2 years is the biggest bull i have ever heard.
It sounds to me like you have not defragged or formated the disk in ages. The windows filesystem has a tendency to get fragmented, and thus one would experience the loss of performance you are talking about. It just has zero to do with the physical hard drive.
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I have to agree with tomas.
I still own the first HDD I ever bought which was a 200 odd MB seagate. Still works fine now. Cost me nearly £350.
You got to love progress , that was well over a £1 per MB and now these days we are talking 20p per GB
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JJ wrote:
Stop........De-fraging a hard-drive is pointless. It will take hours and hours, and you will not notice the real world difference (apart from the old its supposed to be faster so it is effect). you will never gain back the time lost in de-fraging in a performance gain. And guess what as soon as you have de-fragged the drive it gets fragmented again.
I hope you are joking :-o
Claiming something like this, makes you look very clueless..
If you use your pc alot for years without defragging, then you will for sure notice a noticeable increase in performance after defragging a windows box. Defragging can be done at anytime, even while you sleep. Having a very fragmented filesystem is not good for your disk either, as it will have to work so much harder when data is fragmented all over the disk.
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@ tomas
no I am not clueless, if you look at the time it takes to defrag a large harddrive (and I am not talking about if you are sleeping etc) just about the actual time. You will NEVER get that time back in speed increase.
And how often would you suggest defragging your HDD. Because very very quickly after a defrag you will get to the same stage again.
Lets take a user who uses their PC mostly for gaming. They are not going to be writing a lot of data back to the disk, the only thing that get fragmented wouldd be the pagefile. As previoulsy discussed the windows defragger (that most people would use) cant defrag this. So where would be the advantage of defragging
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no I am not clueless, if you look at the time it takes to defrag a large harddrive (and I am not talking about if you are sleeping etc) just about the actual time. You will NEVER get that time back in speed increase.
And how often would you suggest defragging your HDD. Because very very quickly after a defrag you will get to the same stage again.
That part is true, but i doubt most people sit on their pc for 24/7. One can make the pc do it lets say once a month or so at night time or at other times you dont use the pc. Less often if you dont use the hard drive so hard that it is fragmented. I would not defrag if it was lets say less than 10% fragmented. It all depends on how you use your pc.
But anyways.. Sorry for sounding so harsh in my first reply. I read it as if you suggested that defragging would not do a thing even if you do it on a very fragmented system.
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Ok then prehaps I should have said in some cases de-fragging your harddrives is not always nessecary :-D
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JJ wrote:
Ok then prehaps I should have said in some cases de-fragging your harddrives is not always nessecary :-D
Then we agree.. :-)
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Actual harddrive must be replace at least each 2 years if they are used 10h/days, after that they lost 50% of the speed output.
comletely BS!!! :lol: :lol: :lol: I have a raid deck running from 2001 and i can tell you it is far far far from 50% slower"yes it is being frequently bechmarked every 4 weeks.." And the only slowdown is if the swap gets too low or over fragmentation ... Try to format those drives install software again and you will see the speed is far from what you say..
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This is a pretty funny thread. Naturally de-fragging is nearly mandatory unless you have a self defragmenting file system.
Hard drives may get slower over time... the reason is simple. Mechanical wear and magnetic anomalies on the platter surfaces potentially mean multiple seeks trying to locate data... ever try to read a worn or lightly scratched cd? Yeah it takes longer as it keeps re-seeking missed attempts. Really depends on the quality of the drive I guess.
CPU's don't slow down. An external crystal drives the cpu... it either works or it doesn't at the speed it's running at.
It suppose it's possible that they could become flaky and need to be slowed down to run smoothly. If that happens then most likely the cpu was slightly overclocked to begin with.
The speed rating of a cpu is hit and miss and based on tests after production. They make the cpus and then speed test them. Some end up running well at 1ghz and some are only stable at 800mhz. Rather than throw away the 800mhz cpu they are sold as such accordingly. It's possible that a 1ghz cpu may just barely run at 1ghz and runs better at 800mhz..
So thats my 2 cents, and it's worth what you paid for it :)
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Defragging my lappie with Diskeeper, 110 GB, takes perhaps 5 mins - no big deal.
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Think my problem in the past is I have used windows defragger whicch taked for ever and quite often the disk is as fragmented after using it as before
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Umm, did anyone notice the [color=008000]April Fools[/color] notice on the article concerning the "slowing down" of CPUs over time?
@the guy who's computer benchmarked slower some years later with the same set up. If the heat sink and fan on the CPU or VPU were functioning less effectively, quite likely considering the age, then those chips where mostly likely running hotter and that would result in poorer CPU/VPU performance and therefore a lower benchmark score.
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Xamiche wrote:
@the guy who's computer benchmarked slower some years later with the same set up. If the heat sink and fan on the CPU or VPU were functioning less effectively, quite likely considering the age, then those chips where mostly likely running hotter and that would result in poorer CPU/VPU performance and therefore a lower benchmark score.
Only few chips are actually capable of downclocking when overheated (e.g. Pentium 4). Most simply crash.
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What you need to do is every few days, remove your CPU and soak it in a glass of V8 juice. The antioxidants and nutrients in vegetables will slow down the aging of your CPU.
As the other posters have indicated, it seems highly unlikely a CPU will slow with age. You may begin to experience system problems of some kinds, though I dont think this would be "slowness"... most likely a damaged CPU will simply stop working.
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I remember reading a piece about "proton drift" or something like that, talking about how the electron flow can actually move protons over time. Its becoming more of a problem as dies shrink further i believe.
Now, where's that link?
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coldfish wrote:
I remember reading a piece about "proton drift" or something like that, talking about how the electron flow can actually move protons over time. Its becoming more of a problem as dies shrink further i believe.
Now, where's that link?
I think you mean Electromigration, which happens when you over current a circuit... older CMOS CPU's seem to suffer from this effect.
link: http://en.wikipedia.org/wiki/Electromigration
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Only few chips are actually capable of downclocking when overheated (e.g. Pentium 4). Most simply crash.
It not a matter of downclocking. You still lose performance when it over heats because of errors in calculations, or rather operations, and time spend doing the operation again because of the error. Of course if the chip continues to over heat, it will eventually crash. Don't just take my word for it, try it. Take a working Pentium system, run a first person shooter with a frames per second read-out and then slow the CPU fan down. Watch the frames per second drop. We did this in our microprocessor fundamentals unit. I say use a Pentium chip because it more resilient to heat than an AMD chip. It will survive where an AMD will most likely fry.
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JJ wrote:
Stop........De-fraging a hard-drive is pointless. It will take hours and hours, and you will not notice the real world difference (apart from the old its supposed to be faster so it is effect). you will never gain back the time lost in de-fraging in a performance gain. And guess what as soon as you have de-fragged the drive it gets fragmented again.
Ummm ... defragging is a "good thing"!
If your drive is getting fragmented really quickly then you are probably messing with lots of little files or running an app that deals with lots of little bits of files (Bittorrent and P2P apps are good ones for fragmenting a drive quickly) .. to ease the pain a bit you could get the apps in question to work on another drive (rather than your main boot drive), or you could look at reformatting your drive with a different block size, gets to be a bit of a balancing act when you do that though (wasted space vs performance etc).
Just my NZ$0.02 :-)
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well I work in a Computer repair store.. and I can tell you from 7 years of experience. Hard disk drives can
and WILL slow down from 30mb/s to about 1mb/s for example.
NOT ALL hard disks will do this. some models are more prone than others... so there is truth to the above posts...
Just like ANY electrical goods. components WILL fail over time.. And as far as CPU slow down over time is concerned..
Yes it IS possible for reasons mentioned above... socket A Athlons were VERY prone to this..... Again it wont happen to ALL CPU's which is what this post is about.. In fact the CPU in a computer will outlast every other component.. and are ALOT less bound to fail.
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Self repairing Power and PowerPC CPU from IBM:
http://www.theregister.co.uk/2004/08/02/ibm_efuse/
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It not a matter of downclocking. You still lose performance when it over heats because of errors in calculations, or rather operations, and time spend doing the operation again because of the error.
This is complete nonsense - how's the CPU supposed to know when it's wrong? There's no way to do it other than do everything twice - and nobody's designing that way (not in consumer world).
Take a working Pentium system, run a first person shooter with a frames per second read-out and then slow the CPU fan down. Watch the frames per second drop.
Yes, a P4 will downclock when it's sensor shows overtemp - not because of 'errors in calculation'. A lot of calculation done by CPUs is that of addresses and jumps, when something goes wrong there, there's nothing to do for recovering. Either the program trashes data or crashes.
I say use a Pentium chip because it more resilient to heat than an AMD chip. It will survive where an AMD will most likely fry.
Even more nonsense. You should have paid more attention or maybe your teacher has told you wrong: take a PIII and stop the fan. Voilá: crashed. Again: P4s monitor their temp and skip clock cycles (on purpose) when overheated.
AMD were said to fry easily because the Socket A generation had the heatsink directly attached to the naked die. When the HS was not fixed accurately, the chip fried. This does not happen any more with Socket754/939/940/AM2 CPUs.
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@mikrucio
well I work in a Computer repair store.. and I can tell you from 7 years of experience. Hard disk drives can and WILL slow down from 30mb/s to about 1mb/s for example.
They don't actually slow down per se. The slowdown is from read/write retries, or from the extra seeks resulting from bad sector/track (http://en.wikipedia.org/wiki/Bad_sector) remapping.
To check if the HDD has any such blocks, check S.M.A.R.T (http://en.wikipedia.org/wiki/S.M.A.R.T.) attribute 5 (Reallocated Sectors Count) (http://en.wikipedia.org/wiki/S.M.A.R.T.#Known_S.M.A.R.T._attributes). Also attributes 196, 197 and 198 should be checked for.
Regardless, the actual physical disk access is exactly as fast as before. The areas that are not affected by the bit rot work at full original speed, for example.
That being said, it needs to be really severe case before it begins to affect the performance. Couple of dozen of remapping sectors will not affect performance, really.
NOT ALL hard disks will do this. some models are more prone than others.
Some HDDs are much more prone to failure, yes.
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Enough, I don't want anymore forum wars. I can go to the Archlord forums for that. I know what we observed. When we slow the fans the programs performance degraded.
I never said a CPU can get slower with age. I never said P4 don't down clock. My post is a response to someone who wondered why they benchmarked lower with the same system several years apart. Our trial may cast some light on why.
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Right on Bloodline, thanks for the link.
Proton drift, bah, I must've been sleepy when I wrote that.
:-D
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Xamiche wrote:
Enough, I don't want anymore forum wars. I can go to the Archlord forums for that. I know what we observed. When we slow the fans the programs performance degraded.
But you made the wrong conclusion from your observation. The CPU starts to run slower in order to generate less heat because it was especially designed to do so when a temp sensor senses it is becoming too hot.
It doesn't run slower by itself because a hot CPU chip runs slower.
greets,
Staf.
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Depends how you look at this but a graphics processor like the Geforce 6800 has pipelines that are part of it's speed. So if a couple of pipelines should breakdown over the course of a few years you could turn off those pipelines and still have a working card but slower.
This is basically the difference between several models of the 6800. They are just missing some pipelines.
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Fats wrote:
Xamiche wrote:
Enough, I don't want anymore forum wars. I can go to the Archlord forums for that. I know what we observed. When we slow the fans the programs performance degraded.
But you made the wrong conclusion from your observation. The CPU starts to run slower in order to generate less heat because it was especially designed to do so when a temp sensor senses it is becoming too hot.
It doesn't run slower by itself because a hot CPU chip runs slower.
I have read every post on this thread and now that i understand how things works i'll have to agree with you. There is another mystirious issue related to this though:
I've read 3 posts from 3 different users, here and in other forums who claim that their 68040 becomes slower when it is not properly cooled. Not 1 or 2 but 3 reports.
Note: I haven't experience anything similar as an 68040 owner, but my CPU is always cooled actively and it runs at 25mhz only.
I know that 68040s are the most hot chips of the 68k family etc, etc, but still, this doesn't explain what these users experienced. It should only make their CPUs less stable, not slower.
You could classified it as placebo but they seemed quite confident about it from their posts.
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Depends how you look at this but a graphics processor like the Geforce 6800 has pipelines that are part of it's speed. So if a couple of pipelines should breakdown over the course of a few years you could turn off those pipelines and still have a working card but slower.
You don't have the option to deactivate single pipelines without altering the driver (depending on design, modding the driver may not be enough). If one of the pipelines fails, you'd get garbled output and bin the card.
This is basically the difference between several models of the 6800. They are just missing some pipelines.
True. But the different version are detected by the driver and programmed accordingly. If there are no hidden tweaks in the driver and no way to simulate another version by opening/closing jumpers, reflashing BIOS etc., there's no way to make the card stop using the broken pipes.
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Xamiche wrote:
Enough, I don't want anymore forum wars. I can go to the Archlord forums for that. I know what we observed. When we slow the fans the programs performance degraded.
I never said a CPU can get slower with age. I never said P4 don't down clock. My post is a response to someone who wondered why they benchmarked lower with the same system several years apart. Our trial may cast some light on why.
You also compared oranges to apples. A Celeron of that age (466Mhz) has no throttling like a P4 in your tests. Unrelated. Just listen to Piru and Zac and those who agree with them. They know what they're talking about.
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AmigaMance wrote:
I've read 3 posts from 3 different users, here and in other forums who claim that their 68040 becomes slower when it is not properly cooled. Not 1 or 2 but 3 reports.
... You could classified it as placebo but they seemed quite confident about it from their posts.
That maybe so, but who's to say that those users have:
1) made the right conclusion (I can see a speed increase when I muck around with hardware, but along with adding a fan, I also swapped video cards, and perhaps due to some intricate timing issues which I didn't consider due to lack of knowledge [think of Shared-Memory video solutions on PeeCees] I saw a speed increase, therefore my conclusion that adding a fan makes things faster is flawed)
2) are qualified to make the right conclusion (many people can change a fan, but few understand the more or less complete internal workings of a computer to such a degree as to make qualified conclusions. In fact, what's evident from this thread is who is a low level programmer / systems engineer and who is not. I can quite clearly give you a run down of the names without ever knowing anything about these people, and it's simple: a low level programmer / system engineer would swear by what Zac is saying as far as instructions and data in CPU calculations: there's no "error correction" and "retries" and such B.S., other than CRC/ECC calculations on the data buses of course. The CPU either works or doesn't, which will produce a hardware exception, or a Guru Meditation if you will. To think of a modern day CPU as having error corrected address/offset/pointer/arithmetic calculation is simply ludicrous)
Synopsis:
CPUs don't slow down as they age. They die a sudden death.
Hard disk drives and other mechanical devices don't slow down as they age, per se, but can exhibit slower "observed" or "net" behaviour, which is due to bad media (bad blocks) or damaged mechanical parts (motor spins slower, possibly due to power issues, or due to friction caused by heat or cold, physical shock, and other such mechanical failures)