Early-'08 MacPro motherboard question

[sturob]

I read something over on which piqued my curiosity.

A poster mentions that the 2.8 and 3.0 Harpertown/Xeon-based Macs share a motherboard which is unique from the mobo for the 3.2 machines.

How are the motherboards different? Just a slight difference to compensate for the higher power requirements of the 3.2GHz chips? Or . . . ?

I'm just curious. I threw out that word "mobo" just to make it sound like I have some clue about this stuff.

Stuart

 

[newtech]

The theory is that the first shipping 3.2 GHz X5482 Xeon chips are/were the older stepping that had 150 Watt TDP vs the newer stepping that is 120 Watts TDP ( if that is greek to you, the newer version runs cooler and uses less power )

Physically the differences are subtle and related to the higher heat of the 3.2 v. 2.8/3.0. Also the 3.2 uses different heat sinks and thermal compound.


2.8/3.0 MLB part number 661-4449; heat sink 076-1303

3.2 MLB part number 661-4676; heat sink 661-4458