G5 XServe Modification

[dsedohr68]

I was wanting to know if anyone out there has tried putting 2 PowerPC 970MP G5 2.3 dual core processors into a G5 Xserve in place of the two single core 2.3 PowerPC 970FX processors? Will dual core processors run too hot in the xserve compared to the two single cores?

 

[666sheep]

Won't work.

 

[dsedohr68]

why not?

Does it have to do with heat?

what about the 970fx 2.7Ghz G5 processor?

 

[orestes1984]

It's not like a PC, those chips wont work with either the firmware or the OS X software.

 

[dsedohr68]

I don't understand!

Both Apple processors are from G5's, they both work for OS x 10.5.8, both have the same form factor, just one is a dual core and the other is a single core!

The 2.7 is only faster. It is still a 970FX.

My thought is that the only problem would be the heat.

 

[weckart]

On the desktop G5 the dual core G5s have a different logic board from the dual processor G5. Dual core is on the left. Stands to reason that even if the pin out on the processor is the same that other changes including firmware will make DC processors incompatible with earlier logic boards.

 

[dsedohr68]

I do understand the firmware point you are making. I just thought that since I was able to but a G4 500mhz zif processor into my G3 beige and it work that I could do the same here!

 

[weckart]

With the DC G5 system, the memory switched from DDR to DDR2, which is another complication. I am not sure if the memory controller is completely separate or partly built into the processor. If the latter, then you will have a real stumbling block.

 

[dsedohr68]

According to apple history, the memory for the DC is pc4200 DDR at 533Mhz and the DP is pc3200 DDR at 400Mhz. If this is correct the main difference seems to be the ram speed, which is only 133mhz different. the Bus speeds on the CPU are either 1.0, 1.15, or 1.25 Ghz.

 

[weckart]

PC2-4200, which is DDR2.

http://support.apple.com/kb/sp37


I own one of the the DC G5s.

 

[Intell]

You cannot switch MP and FX processors. Even if you could, the locked bus speed would render them very slow. Around 900Mhz each. This is like taking a Prescott Pentium 4 and putting it into a Williamsgate Pentium 4's board. It won't work because of the cache and fbus difference, even though it fits into the board.

 

[orestes1984]

This, factored in with the fact that you cannot adjust bus speeds on a Mac more often than not without physically actually altering the motherboard. They're the wrong bus speed and even if you could get them to fit the firmware on the board probably wont recognise the chip.

 

[goMac]

I don't understand!

Both Apple processors are from G5's, they both work for OS x 10.5.8, both have the same form factor, just one is a dual core and the other is a single core!

The 2.7 is only faster. It is still a 970FX.

My thought is that the only problem would be the heat.

You can't swap processors in G5s for a lot a lot of reasons. Firmware, hardware, chipset, etc.

They aren't built like PCs. They are built specifically for one kind of processor (even most of the time at one speed) from top to bottom.