"Late 2005" Power Mac G5 CPU upgrade — #6

Post #6 by firebottle

Source Forum	"Late 2005" Power Mac G5 CPU upgrade — #6
Category	Hardware
Post Date	Wed, 3 Apr 2013 - 11:58
Original URL	https://68kmla.org/bb/threads/quot-late-2005-quot-power-mac-g5-cpu-upgrade.27747/

Post

If you are going to take apart your two machines anyway, it may be worth looking at the part numbers on the motherboards. A quick Googling suggests that there may only be part numbers for the "dual" PCIe board (which used one CPU socket) and the "quad" PCIe board, which used two CPU sockets. If this is the case, probably each motherboard was certified to run at the top 1250MHz implied for the G5 by a 2.5GHz processor. The slowest PCIe systems were dual-core 2.0GHz models if I remember correctly, so it's not that big of a stretch to imagine that the boards were certified to run between 1000MHz and 1250MHz.

This is what I was thinking too. And the CPU card sets the speed of the bus.

Although beyond that I have no idea what's necessary and whether it's just popping out a daughtercard and swapping the new one in (like the PowerMac 7300) or if it's a socket directly on the board with a heatsink that attaches separately and needs to be re-equipped with heatsink paste (which could turn a "simple processor swap" into an evening's project.)

Looking at the pictures in the service manual, the CPU cards seem permanently attached to the heatsinks.

The heatsink/CPU assembly pulls straight out once you loosen the screws.

If you are going to dedicate an evening or so to it though, I'd try just the processors first.

I was going to try swapping CPUs, but first I have to find a 4mm "ball-head" hex wrench...