How far can I push an 040/25?

[that_punk_guy]

reallyYyYyY... ?

;-)

[darksun9210]

I had a Warpengine 040 running at 28mhz, and as the crystal was socketed, i thought it would be a nice easy overclock. but could i get a 33mhz crystal? nope.  managed to get a 40Mhz crystal chip, and remembering how hot my old cyberstormII 040 got, i pulled the little heatsink off and cleaned off the glue and heatsink paste. and the chip turned out to be a 25Mhz version (full FPU, MMU etc.)

bolted on a BIIIG arse heatsink and fan with a spot or two of heatsink grease, popped in the 40Mhz crystal, booted up fine. nothing flaky, or after continuous tests (involving AIBB and Quake) it all looked fine. one thing was puzzeled me. in stuff like show config, it didn't seem to think it had an FPU. this struck me as ok, as the 040 may have disabled the FPU due to the speed and possible core temperatures it was running at. i dunno. but even tho it reported no FPU, the FPU tests and Quake, and other FPU requiring software ran fine, so shrugged my shoulders and carried on. if you are over clocking an 040, bear in mind COOLING COOLING COOLING! and heatsink thermal paste can make all the difference!
(just not too much, just enuff to fill the imperfections in the surface of the chip and base of the heatsink. if you are going to glue the 'sink to the chip, but spots of glue on the outside of the chip/sink so you arn't interfearing with the heat dissipated to the heatsink) :-)

[Amiga1200PPC]

I cannot remember exactly anymore.
PC - or something similar where prototypes
XC - normal series production
RC - has passed special very demanding test

[jonbyk]

Sent defective quaddouber back to Sonnet.  The  new one booted right up at  55Mb.

Nice.

Jon Byk

[zipper]

XC is normal but early production version.
RC is ceramic case.

[bloodline]

OT: I would really love to see a 68K built using a bodern 0.13nm process :-)

[TjLaZer]

I have a Apollo 1240/25 and I can do 33MHz just fine (with Heatsync and fan), but cannot do 40MHz.  I could maybe with a really good cooling setup and if I was in a tower.  I can boot into WB @ 40MHz but after 5 minutes sys crashes.

[FlagshipAmigaLover]

Hi lorddef,

I do not recommend over-clocking a processor.  If you need a faster 68040 then buy one.  Try to get the MC68040, not the XC68040.  The MC68040 runs cooler and a little faster then the XC version.     :-)

[voytech]

FlagshipAmigaLover wrote:
 The MC68040 runs (..) little faster then the XC version.     :-)

 :-D  :-D  :-D

[QuikSanz]

Hi,

I'm in PPC's camp. overclock it. then you'll have a great excuse to replace it with an 060.
Ah, power, gotta love it.

Chris

[Neo]

If you own a Cyberstorm or Blizzard board you should be able to
overclock the 68040 as much as it can stand. On some older accelerator
boards you may get trouble with the board itself if trying to
overclock.

I currently run my 68040/25 at 40MHz and it has been running fine for
several days now, and it doesn't generate much heat. I've added a fan
to the CPU before I put the lid on my A3000D.

I have been thinking to try 45 or 50MHz. Have to get some oscillators
to do that though. (I love the smell of burning sillicon)

[utri007]

I have apollo 040 40mhz i tied to overlock it to 50mhz it didn't work it stops to green screen.

Didn't work without memory either.

I know its possible to overclock to 50 mhz, I know some guy who have did that years ago and still using it.

Some Apple accellators have 57 mhz 040