Which CPUs do you love or hate

[joetee]

Hi,
> Just a roundup of the CPUs over the years that you loved or hated for whatever reason.
> Hate: 8mhz 68000
I dont hate because the first Amiga 68K because the custom chips let it run full speed - in color: sorry Apple!
Remember: A 68000 @ 7.159 Mhz (on an Amiga, obviously!) CREATED the entire "demo scene" with what you_could_do on a stock Personal Computer.

I love how simply adding a 68010 or an ICD (or Aminet!) 14Mhz Accelerators so cheaply and totaly upgraded the base machine bought in 1985.

Thats right: 1985!
...Were ya borne yet?...
*heh*

I will respond to the rest late...

[Karlos]

Depends on what your definition of "an operating system using more than one core" is

What would interest me more than just having one program crunching numbers within one core, another crunching numbers in another core, a third crunching numbers in a third core etc is if the operating system itself could could be split across the cores running a different task in each core,

I dunno where you are getting your impression from but the OS does do exactly this. If one core is busy, any newly created processes will be put on a different core. Also, most kernels allow a process to move between cores whenever the task scheduler decides to redistribute the load. For example, on my machine, a single-thread process using 100% cpu load is actually distributed across all four cores (although only one one of them at any instant), spending approximately the same amount of time on each one. That's probably better thermally for the CPU than having one core at 100% and the other's permanently idling along.

or i could get one program to split itself across each core.  I hardly ever need to encode more than on video/dvd at the same time, but I'd like to have four cores all working to decode that single DVD at the same time.  At the moment this doesn't happen particularly  well, if at all, as most software and the OS is not designed to detach into parallel tasks like that. Most benchmarks I've seen from dual core systems are at best 30-50% faster than a single core at the same clock speed, and for some benchmarks with some dual core cpu's the dual core can even be slower.  (Windows 7 might be better, i haven't had any experience with it)

Programs must be written to support this. Presently, the only way for an application to do this would be to create several threads and give a portion of the workload to each one. This assumes that the job they are doing supports this type of parallelism. Many jobs don't. There's no magic way to automatically fork a process into subthreads and divide work between them.

The next generation of C++ aims to include language-level support for writing multithreaded code, which will certainly help.

Incidentally, I was using 3 of the 4 cores to encode a single DVD. Each one was working on a subset of the total number of titles on the disc. I could have used all four cores but the number of titles was an exact multiple of 3 and I was doing other stuff at the same time, so I launched three processes. So, in effect I was getting exactly what you were asking for.

[bloodline]

The next generation of C++ aims to include language-level support for writing multithreaded code, which will certainly help.

Apple have added blocks to C...

http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars/10

this goes hand in hand with their grand central dispatch subsystem...

[B00tDisk]

Maybe,
which is fine with me, I'm having fun with my mobile device...

Oh no, no, don't misunderstand me.  I think it's absolutely wonderful for you and Apple that you've agreed to behave yourself while you lease their hardware!  No, seriously, that sounds like you guys have a great arrangement.

[persia]

Actually you own the iPhone, so you can do anything you like to it, but Apple won't help if you break something, that is Jail breaking voids warrantee.  I can live with that.

[Karlos]

Apple have added blocks to C...

http://arstechnica.com/apple/reviews/2009/08/mac-os-x-10-6.ars/10

this goes hand in hand with their grand central dispatch subsystem...

Actually, I find that absolutely disgusting. New syntax should not be added to C for any reason whatsoever, unless it is an official ISO standard that can be adopted openly. Which pretty much hasn't happened since C99. For multithreading, I would much prefer a standard library of functions. Actually changing the language syntax breaks portability in a way that's incredibly awkward to work around. Redefining the ^ operator for passing a block of code isn't even readily ported to C++ where operator overloading is a language feature.

Now, C++ added further syntax to C but it didn't change any meaning of existing C syntax (ok, there are a few small gotchas) but whenever something new is added to C++ nowadays, it's via the STL.

[StormLord]

Actually you own the iPhone, so you can do anything you like to it, but Apple won't help if you break something, that is Jail breaking voids warrantee.  I can live with that.

well, jailbrake doesn't void warranty... ofcourse you have to restore with apple firmware before claiming warranty ;-)

but the thread was for cpus so:

LOVE: 030,060,ppc750,ppc7455,Duron,athlonXP,K64,Core,core2

Hate: 68000,040,Celerons ALL!,Pentium4 ALL,ppc970fx

athlonXP and durons are loved because of their age, otherwise they have almost the same performance per tick with G5 (ok G5 is better on vectors, have THE fastest BUS till now, but also newer)

@piru
fastest G4 was 7455(even it was older) and not 7447/7448, because it supports L3 cache
and you know the problem with bus speed on G4....

[DIBBEERZ]

to be quick and less complex
liked
moto 6800 classic and 030
the slot  pentiums for ease of throwing in and workin for long periods cheaply
and my amd 64x2 cause its current  works and is ok

worst cpu
to be avoided at all cost is the cyrix i have under clocked them many times to work at all !

[B00tDisk]

worst cpu
to be avoided at all cost is the cyrix i have under clocked them many times to work at all !

This, oh god, this.

I want to invent time travel specifically for the purpose of going back in time and stopping the Cyrix company from being formed, and the 6x86 line from coming out.  Damn my mid 90's needs for a cheap Pentium clone.

[B00tDisk]

Actually you own the iPhone, so you can do anything you like to it, but Apple won't help if you break something, that is Jail breaking voids warrantee.  I can live with that.

You do not own the iPhone.

[Zac67]

What most tend to forget is the fact that a single core would always be faster than a dual core running half its speed (or quad respectively) - 1x 6 GHz > 2x 3 GHz.
There is no 6 GHz? Yes, that's the point. The industry has changed over to multicores as the only way to considerably raise performance since there's no way to increase clock speeds any more. There are gentle increases as well as gradual architecture improvements, but nothing to show off to any potential customer.

[tone007]

What most tend to forget is the fact that a single core would always be faster than a dual core running half its speed (or quad respectively) - 1x 6 GHz > 2x 3 GHz.
There is no 6 GHz? Yes, that's the point.

I know I personally tend to forget situations that don't exist.

[bloodline]

You do not own the iPhone.

Sorry, but what does a year old editorial piece have to do with ownership of the iPhone...

I bought a device with an operating system, that I can use on a daily basis... I can buy apps for and I can write my own apps for... It's pretty powerful for the price and quite innovative... but if I modify it beyond the manufactures specification (like swap out the installed firmware) they have stated that they wouldn't provide me with any support...

I am of course referring to my A1200... but the above equally applies to my iPhone...

[stefcep2]

I dunno where you are getting your impression from  

from this:

 For example, on my machine, a single-thread process using 100% cpu load is actually distributed across all four cores ****(although only one one of them at any instant)****, spending approximately the same amount of time on each one.

and this

***Programs must be written to support this. ****

and this

The next generation of C++ aims to include language-level support for writing multithreaded code, which will certainly help.

hence my statement that multi-core CPU's aren't used particularly well at this time.

[Karlos]

Wait, hang on. That was given in answer to your earlier point. Didn't you say you'd prefer it if the OS distributed the work between the cores? Well, that's exactly what the kernel does do. To the extent that even a single thread will move from one core to another depending on the existing load on each core and for improved thermal distribution (if nothing else).

A single thread of execution, by definition cannot run on several cores concurrently. Do not confuse multi core with superscalar execution. They are not the same thing and for what it's worth, each of these multiple cores is superscalar and nicely pipelined too. Each one is thus executing more than one sequential instruction in whichever thread they happen to be executing at any instant.

Now, as for the issue about writing stuff for multi core, you have to accept that not every computational task is parallelisable. Therefore there will be some things that cannot on their own take advantage of more than one core. However, you must bear in mind that on all multitasking operating systems there are usually many threads that are ready to run and the scheduler has to pick just one of them per quantum. Not so on a multicore. It will allow as many threads to execute per quantum as the hardware will allow. From a throughput perspective, running four threads in one quantum is up to 4x faster (assuming no interdependencies) than running one each for four successive quantums. Better throughput means less latency for all tasks.

What I am saying is, that unless you use a single application on a single-tasking "OS" (or MacOS classic as it's more commonly known :lol:), it's impossible to not reap a performance gain from multi core in general use.

The principal exception to this rule is when you want to run a single, very CPU intensive task that cannot ever be optimized for parallel execution where a single core processor may offer a price/performance benefit over a more costly multi core part that can't run that one task any faster.

Now, amiga users are fans of multitasking, after all it was always our OS's strength. Seems a bit daft to try to ignore the clear advantage of a multi core CPU in an SMP capable multitasking OS.

[Karlos]

Having used a quad core, there is absolutely no way I'm moving back to a single core for a main machine, unless it can match the same overall throughput. However, it'd have to be at least 10GHz to manage that.

-edit-

Actually, looking back at it, I've been enjoying multicore computing ever since I got my first PPC board. A comparatively simple task (by current standards) such as playing back MP3, on the 68040 was a joke. It could manage mono 22kHz and there was no cpu time left to do anything else. That all changed when the PPC decoding engine was running in AmigaAMP. That whole arrangement was far less efficient than SMP (unavoidable considering they are two totally different processors) but the benefit of having a separate CPU core to dump the job onto was clear even then.