How far can I push an 040/25?

[Dr_Righteous]

Get some crystals and a decent fan... Try it yourself. As long as you have a decent fan, you shouldn't have to worry about cooking the chip. Ramp it up untill you experience instability, then take it down till things settle. Oh, and you might wanna socket the crystal if it's not already done.

Bottom line... Some chips can take more than others, so experimentation is really the only way to find out.

[jonbyk]

If anyone is still reading this thread, the Quaddoubler that didn't work was returned to Sonnet.  I got it back last week. Put it in, and Eureka! 68040/55!  Quite fast.  Very nice.

Jon Byk

[Damion]

BTW it's pretty fast. According to SysInfo it's about the same speed as my Apollo 1260.

Could one of you guys with this board please
post the MIPS/MFLOPS rating from SysInfo or
better yet SysSpeed? I would appreciate it..

[CRL]

Hi All-
     On the strength of the above advice I just got a quaddoubler (arrived UPS last night).  Popped open my totally stock (well, I do have Oxypatcher running, and Fblit too) A4000, stuck quaddoubler on the daughterboard (the "b" model hangs off the side where there is room for it, something I was worried about!) and put everything back together easier than puting in a new ROM.  It booted right up just fine.  AIBB tests show it to be mostly 2.02 times faster than a stock A4000/40.  Exceptions: drawing the beachball is 3 or 5 times as fast (oxypatch effect?), memory test is still stock speed (half as fast as a A3000).  Some of the tests were only 1.5-1.8 times faster, I presume ones that had a memory component.
   
     Subjectively, the GUI was faster, the icons just popped into the windows.  I tried playing a few games and they all seemed to work, although megaball developed an odd lock up that needed a re-boot to get out of.  Breathless seemed to look smooth at screen sizes I had found unusable before (I didn't try above 320-200 as that seemed to get a little jumpy).  Genesis (the old fractal scenery generator from years ago) painted scenes fast enough to be fun again, which made me smile since that was my main reason to spend the $$ on a speed-up.
 
       My major disappointment is that when I tried to play avi files on my OS3.9 Action tool, they looked slower and rougher than a plain vanilla 68040/25 system. (Anyone have a suggestion here?)
   
    I spent $117 (with shipping) to almost painlessly double the speed of my system.  I read somewhere that you should never upgrade less that 4 times speed, however the next plug and play step up for me would be some kind of 060 card at a much steeper cost.  $100 now and then seems right to spend on a beloved old hobby computer.
Yours-
CRL   :-)

[Karlos]

@CRL

Perhaps the AVI playback is demanding too much and causing your overclocked CPU to overheat?

[Jagabot]

I'll throw in my 2 cents here.  All referring to using a 3640 board and not a 3rd party 040 accelerator card like a WarpEngine etc.

I've overclocked around 75 different Amiga 4000's in my time, they all react differently. It's not a case of the chip, or the 3640, but the motherboard (I know, it's wacky).  You can take a perfectly stable 3640 with a 040/25 running at 33MHz and move it to another 4000 and that 2nd machine wont work,

First, be sure you're using 60ns SIMMS (not 70ns or 80ns) or it'll screw up the timing and just cycle the hard drive when it tries to boot if you run over 25MHz.

Second, most 3640 boards will support a 40MHz 040 chip, but the 4th (last) bank of memory on the motherboard will not be seen (this is the case in every board I've tried, I have heard of a case or two where a person's machine works just fine at 40Mhz with a 3640 although it never has for me).

Third, most 25MHz 040's will run at 28MHz, 30MHz, and quite often 33MHz, but even with a water cooler I've never managed to get one to run at 40 (But I have gotten 33MHz ones to run at 40 with no sweat) again, however, most motherboards will cease to see that last 4MB of RAM in bank 4. Just wacky. It's all trial and error, plus having had the benefit of having 20 new 4000's at my disposal to find one that ran well at 40 (minus the 4th bank issue) was nice. I always personally owned a 40MHz 4000 with a stock 3640 because of that.

The trick is to find oscillators of various speeds so you can step your machine up a few MHz at a time until you find that magic point where it runs stable (my 3000 ran great at 50MHz with a 33MHz 030 for example, my buddy Rob's would only work at 40). I also had a 3000T that ran an 040 25 at 33Mhz but not at 28MHz. Amigas are strange that way, but that's part of the fun! :-D

I do know of a supplier in France who has every oscillator under the sun www.radiospares.fr (but the site is entirely in french so you have to have a good idea of what part number you're looking for if you don't read french - babbelfish might help here as well). If somebody here knows of a good north american (or asian) supplier of oscillators I'd like to know myself.  :-)  

[LaPTuNa]

I think the sonnet doublers used a 040/25 clocked to 50mhz. I've got one in my 4000 (although she hasnt be turned on but twice in the last two years). Its on the A3640 rev3.1. Has some kind of heatsink chill circuit thing on it.

[CRL]

Hi Jagabot-
The Sonnet quaddoubler replaces the 68040 with a little board that has a 50mhz '040 plus cooler.  That is, AFAIK it doesn't speed up anything on the daughterboard at all, just takes care of CPU business at double speed then looks like a 25mhz chip to the board.  Gee, I could be all wrong, but I'm not having trouble with reading all 16megs of memory.  Not real super memory chips either if I recall correctly.  Somewhere above in this thread there is a pointer to extended descriptions of the Sonnet device.  Seemed like a nice way to go faster to me.
CRL  :-)

[AmigaSource]

   Here's some more info.  Sonnet used to advertise their quad doubler for the Amiga market in Amiga World Magazine back in 92-94ish time frame.  A few years back I purchased one off of e-bay for my A4000.  But due to the way the socket was mounted on the version I had I was unable to use it.   When it was mounted to the 3640 the rest of the quad doubler hung over and covered most of the daughter board slot.  So it was either the daughter board or the quad doubler...  The doubler is in the garage collecting dust.  
   Just for fun I called Sonnet to ask them about the  design change and by this time tech support didn’t even know what an Amiga was.

[Jagabot]

Hey CRL, thanks, that's good stuff to know. I'm sure I'll be passing that along to quite a few people who don't frequent Amiga.org! Thanks.

(Like I said, what I posted was in regard to only the Commodore 3640 board and pushing the cpu on one. But this Sonnet will be much more handy.)

[vortexau]

From to the Red Planet

Beagle will be set free to enter the atmosphere at 700 mph. Once it has slowed down, parachutes will open to brake it even more. Finally, large gas bags will inflate to cushion the probe as it bounces to the surface.  Once still, its solar panels will open up and cameras will start to peer around the site. During the first few hours it will send its call sign - a song specially recorded and composed by the pop group Blur - back to Milton Keynes via Nasa's orbiting Odyssey craft. Beagle 2 weighs just 75lb - and carries 24lb of scientific equipment. It is tough enough to survive the shakes of take-off, and a bump on landing likened to pushing a computer off a desk on to concrete and expecting it to work.

[vortexau]

Computer punishment!
Should computers be legally responsible?
"Are There Senses in
which a Computer may Properly by Held Responsible for its Actions?" by J.P.A.
Race from Brunel Univeristy, UK[/i]

 "There are three aspects of punishment:

      Retribution:[/i] the need for society to get its revenge on the wrong-     doer: a basically irrational (but quite understandable) emotional     response.  If this means pushing a computer system over a cliff     after it has driven someone to suicide through sending them wrong     electricity bills, we can understand it. [...]

     Rehabilitation:[/i] In this sense, the aim of punishment is to improve     the individual for his own sake and that of society.  In the case     of a computer, this may involve re-programming or the indication     to the computer that its previous response had been wrong, so that     this reprimand is stored as a new parameter value to adjust its     future behaviour.  The fact that we did not use a cat-o'-nine-tails     or the brig does not mean what we did was not punishment, any more     than it is not punishment - of a severe kind - if a court-martial     reprimands an officer who runs a frigate aground.
   
    Deterrence:[/i]  The fact that [this computer system] is punished should     be communicated to other computer systems working on similar things.     [...]

 :-D

[Amiga1200PPC]

I'm running a MC68040XC25 on a BlizzardPPC at 33 MHz here.
It's very stable even at summer time temperatures.
I didn't try to overclock it even more, but I guess it could do much more than this.

But I must warn you, this is a military spec 040, don't try to reproduce this at home!

[Cyberus]

could someone enlighten me as to what the different suffixes mean? e.g. 68040XC25 (I know the last two digits relate to speed) as opposed to 68040RC25?

Thanks
edit: nae worry - I just discovered I'd bookmarked a site detailing just tha earlier this year

[PPC]

Get an 060 it roxXx!

[that_punk_guy]

reallyYyYyY... ?

;-)