PowerPC 604 swap

[plb007]

Hi, 

As part of resurrecting an old PM8500, can I use the processor card from a 8600/9600 series ? I have one that can act as a donor but it's a 350 Mhz processor. I know the internal bus speed won't go faster, but I wonder if the computer will/must be able to boot with that processor card. 

Regards, 

 

[beachycove]

As I recall, the “Kansas” machines and the 8500 are sufficiently different as to make this impossible. Oddly enough, they will nevertheless take the same G3 upgrade cards.

 

[trag]

No, that will not work.

Apple X500 and X600 machines can all use the same CPU cards with the following exceptions...

There were two models of Power Macintosh 8600 and two models of Power Macintosh 9600.    The second models with the same names are technically a Power Macintosh 8600 Enhanced and a Power Macintosh 9600 Enhanced.   Also known as Kansas or Mach V (Mach V more correctly refers to their special CPU card).

The Enhanced 8600 and 9600 have some changes to the power supply pins in the CPU slot such that they cannot use the CPU cards of earlier models.

The Enhanced 8600 and 9600 shipped with PPC604ev based CPU cards with an In-Line L2 cache on the CPU card.    These CPU cards cannot be used in earlier x500, x600 machines nor in the clones.

The Enhanced 8600 and 9600 machines look almost just like the previous model.    They can be distinguished in a few ways.  

A)    If you check the ROM revision in Apple System Profiler it will be 77D.34F5.   On the previous model it will be 77D.34F2.  On the 8500 and 9500 it will be 77D.28F2

B )  If you examine the logic board ROM chips (four chips about .5" X 1.1" with 22 pins down each long side, 8600 ROMs are on the back) the enhanced set is marked 341S0380 through 341S0383.     Unenhanced 8600/9600 has markings 341S0280 - 341S0283.   8500/9500 reads 341S0168 - 341S0171.

C)   The 8600 enhanced lacks the Cache DIMM socket.  The holes are there, but the socket is uninstalled, because the cache is now on the CPU card.    The 9600 Enhanced lacks the on-board cache chips (four square chips ~1" square to front of machine from PCI slots.  The solder pads for the chips are there, but the cache is not installed.  Cache is soldered to the logic board on the 9500 and original 9600, but on the CPU card in the 9600 Enhanced.

Apple CPU cards that run 250MHz or faster are Mach V cards meant for the 8600/9600 Enhanced and do not work in earlier machines.   However, there were 250 MHz 604E cards from Power Computing, Umax and perhaps PowerLogix or XLR8 that will work in the earlier x500, x600 machines.    

However, Power Computing CPU cards meant for the PowerBase, PowerCenter, PowerCenterPro and PowerTower will not work in Apple machines.  Only Power Computing CPU cards meant for the PowerTower Pro and the PowerWave work in Apple machines. 

 

[trag]

As I recall, the “Kansas” machines and the 8500 are sufficiently different as to make this impossible. Oddly enough, they will nevertheless take the same G3 upgrade cards.

Third party upgrade makers built in compatibility.     The main difference in the CPU slots of the two generations of machines is the arrangement of power supply pins.  I think more pins are devoted to 3.3V supply on the Kansas/MachV/Enhanced machines.   So it was pretty easy for the upgrade makers to compensate.  All the logic board signals are sitll the same, as the same chipset was still being used on the logic boards.