Extreme Amiga overclocking.

[redrumloa]

As mentioned in an earlier thread I am stocking up on crystals for overclocking. The first order arrived yesterday and will be listed shortly. But that's not the point of this thread.

I'd like to hear people's experiences overclocking their Amiga hardware. Id like to hear not only the traditional drop in replacement of the accelerator crystal, but extreme modifications. I am testing an unusual modification atm that has me experiencing quite impressive results.

So gimme stories:-)

[PMC]

Yeah,

I bought a stock Apollo 25Mhz '040 some years back.  Knowing that '040's have cooling issues I overclocked it.  First to 28Mhz, then 33Mhz and finally 40Mhz.  

Worked a treat.  At least it did until the chip fan decided to detach itself...  I now am presented with a red screen upon startup.

Oops.

[blobrana]

@PMC
Hum,
that was a bit excessive huh?

But i sense that if you reseat the ROM chips then you may revive the computer...






[It`s possible to mimic that screen with a nuclear EM pulse, though]

[Vincent]

And buy a better fan/heatsink for it :-)

[Acill]

I overclocked a CS MK II to 80MHZ and used a liquid cooling block on it. It worked great all the way up to selling it and converting it back to a 50MHZ config.

[Karlos]

I heard that someone got one of those SDRAM equipped CT060 cards for the Atari running at 100MHz. Now if there was a way to get one of those into an A1200 :-D

[PMC]

@Blob,

Well, it worked for over four years at 40Mhz with no problems with stability.  

For good measure I installed a heatsink between the CPU and fan, but I foolishly failed to periodically check the adhesion between the heatsink and fan.  

I'll check the ROMs as you suggest and will report back.

[redrumloa]

Is the Amiga 4000D schematics online anywhere? I have just about every shop manual except the A4000:-(

[amigamad]

Try here http://www.ianstedman.co.uk/Amiga/schematics/schematics.html

second one for 4000 downloads but its in iff format. :-?

This is a better one to get it from http://amiga.serveftp.net/schematics.html :-)

[swift240]

I am just wandering, I have an Apollo 030 Turbo Mk-III running at 40Mhz no FPU with 32meg Fastram, could this be overclocked to 50Mhz do you think, or is that out of the question?
Bye the way, I am using a heatsink and fan ontop of the cpu that came from a Pentium 233mhz., with the proper heatsink cream and an elastic band for just in case.
It dont actualy need this but I thought what the hell stick it on any way.
Never had a problem.....
Mike.... :-)

[delshay]

dont overclock blizzppc to 280mhz with ram setting all turned off..60ns **maybe** fine on some cards..

one of my blizzppc has stop seeing bvision & fast ram due-to the above overclock..

[redrumloa]

Well this is interesting..

System:
CSPPC 200 & 060/50 (not overclocked yet, stock speed)
Prometheus with Voodoo 3 2000 (not overclocked yet)

I have done one small, unusual modification that isn't even an overclock, and I am smoking all the 3D benchmarks on AmigaSpeed.de! Those systems has faster CPUs and faster GFX cards. Hmm...

This is getting very interesting...Very interesting indeed...

[Karlos]

@Red

Bus performance is *extremely* important for 3D applications on existing classic amigas using eg Warp3D.

The faster you can shovel data to the card the better. All existing voodoo3 cards (and believe it or not, even the permedia2 half of the time) can consume vertex data at a much faster rate than the bus can deliver it. On slower 680x0 systems you tend not to notice since the CPU is the bottleneck, but with faster CPUs (eg the PPC and fast 060's) the bus becomes the dominant factor in 3D performance.

[delshay]

if i remember the difference between 60ns & all the memory switched off on the blizzppc is as much as 3MB sec...you can see the diff in wipeout 2097..

ahi
800x600
060 overclocked 66.6
ppc 603e 280Mhz..overclocked


do not switch off memory on blizzppc at this speed..

[BoingBoss]

As always, I do not recommend over-clocking a processor.  In fact, some processor boards for the Amiga 2000 need to be "under-clocked".  For instance, the Progressive 2000 / 040 board has a 25 MHz 68040 chip that is clocked at 28 MHz.  It uses a 56 MHz crystal.  I am looking for a 50 MHz crystal so I can clock this board at 25 MHz, like it should have been done to begin with.  Then this board will be a lot more stable and will run much cooler.  If you guys actually need a lot of speed, then get yourself a PC computer.  The Amiga was designed to do WORK.  It was not designed to be fast.  To give you an idea of what I am talking about think about this:  a car is faster then a locomotive, but a car can only pull 1 or 2 more cars.  A locomotive can pull hundreds of cars.  One was designed for speed and the other was designed to do actual work.