Chinese 68060 Rev 6

[matthey]

I'm the guy that did the CSMK3 at 80MHz with 50ns SIMMs. I have since had to slow it down as I had a few errors. I think it's a limitation of the memory controller chip and not the 50ns SIMMs or rev 6 68060 (has heatsink & fan). I have a 75 MHz oscillator on the way. The CSMK3 has a place for a 2nd oscillator to clock the 68060 separate from the SCSI and motherboard clock input. Most accelerators do not allow this and changing the oscillator may also overclock the motherboard. This does make the custom chips faster but can cause problems when overclocked too much. The AGA is a little better at overclocking than ECS in my experience and you should get away with at least a 60MHz oscillator if that clock is fed into the Amiga (it's actually halfed). You want to start with lower amounts of overclocking and work your way up feeling how hot chips get and looking for errors. If my guess is correct, you will be limited to about 60 MHz but I have no experience with your accelerator. You can find some great info on Amiga overclocking here...

http://members.iinet.net.au/~davem2/amiga.html

I found my Crucial 50ns 32Mb EDO SIMMs on Ebay. They are not common but do pop up from time to time. Most if not all will be EDO. Make sure they are 5 volts!

Your voltage regulator should be fine. The voltage doesn't change with a faster processor. It draws more amps.

[matthey]

I got my 75MHz oscillator today and so far it's been rock solid in my CSMK3. Here's my bustest...

BusSpeedTest 0.19 (mlelstv)   Buffer:     262144 Bytes, Alignment: 32768
========================================================================
memtype   addr       op         cycle     calib         bandwidth
fast      $08AB0000  readw      35.7 ns   normal      56.0 * 10^6 byte/s
fast      $08AB0000  readl      58.6 ns   normal      68.3 * 10^6 byte/s
fast      $08AB0000  readm      59.7 ns   normal      67.0 * 10^6 byte/s
fast      $08AB0000  writew     39.6 ns   normal      50.5 * 10^6 byte/s
fast      $08AB0000  writel     79.3 ns   normal      50.5 * 10^6 byte/s
fast      $08AB0000  writem     82.8 ns   normal      48.3 * 10^6 byte/s
chip      $00020000  readw     859.6 ns   normal       2.3 * 10^6 byte/s
chip      $00020000  readl     860.1 ns   normal       4.7 * 10^6 byte/s
chip      $00020000  readm     859.8 ns   normal       4.7 * 10^6 byte/s
chip      $00020000  writew    565.3 ns   normal       3.5 * 10^6 byte/s
chip      $00020000  writel    565.6 ns   normal       7.1 * 10^6 byte/s
chip      $00020000  writem    565.8 ns   normal       7.1 * 10^6 byte/s

Nice memory speedup from overclocking. Processor speed is still more important because of
the caches though. I have heard of a guy with an Apollo '060 that claimed 100 MHz. Bad
thing about the Apollo is the bad/broken SCSI. The Quickpack '060 with EDO SIMMs would
have faster memory access than my CSMK3. I wonder how well they overclock. One last note
about SIMMs. They should be as least as fast as they are marked but some that are not
marked fast are. For example, I have some 16Mb SIMMs that are marked 60ns but tested 47ns
on a SIMM tester. Some SIMMs may work but cause problems or produce errors later when they
heat up. Some accellerators just don't like certain SIMMs. The best thing is to try
different SIMMs. Also, fit as few of SIMMs as possible during testing.

[matthey]

@-D-

Overclocking the CSMK3 to 75 MHz now gives better memory performance than the stock Quikpack 68060 with EDO (+15-20%)...

http://www.hd-zone.com/amiga/quickpak.html

I would like to see what an overclocked Quikpack would do. I've never heard of anyone overclocking one by very much. If the Natami ever comes out it would probably be able to double these numbers!

I currently have the CSMK3 in my 3000T (no AGA) but I'll try putting it back in my 4000T pretty soon. I have Clickboom Quake and QuakeGL (Mediator+Voodoo4) installed and the QuakeGL is a little faster, looks nicer, and is less buggy. I play in 640x400 as 640x480 slows down too much at times. The Voodoo4 isn't very well utilized on the Amiga or more would be possible.

[matthey]

@KatManDEW

There were some 68060's with 71E41J mask (shrunk die size) that typically overclock from 75-100MHz and produce less heat. Most were marked MC instead of XC. I don't see any more available at the moment though.

You need to change the voltage in your accelerator from 5V to 3.3V for your upgrade as well as having the proper oscillator.

edit:

Actually, there are these 60MHz versions...

http://cgi.ebay.com/Motorola-MC-68060-RC-60-71E41J-100-WORKING_W0QQitemZ260361281511QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item260361281511

The others were 50MHz and much cheaper.