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installing a second CPU in 2008 Mac pro...

B

Bunking

macrumors newbie
Original poster
Apr 7, 2015
8
0
Hi All,

So I have this old early 2008 mac pro that has a single quad core xeon 2.8 Ghz processor in it and I would love to put another in to make it dual CPU. However i'm finding a lot of conflicting information on this subjects as to whether this is even possible. If it is though - does anyone know of any processors that would work as second CPU's?

bit of a noobie here and any advice would be greatly appreciated

thanks!
 
It can be done. All 2008 MPs have two spots for CPUs even if it is only running on one. You would need to purchase a heat sink for the second slot - costs about 200 bucks. You would also need your CPUs to match. A pair of 3.0 gHz procs can be had for around 100 bucks. I would not recommend the 3.2 gHz as the TDP is double the 2.8 or 3.0.
 
hey man thanks for that - I will certainly be looking into that. do you have any specific models of CPU you would recommend?
 
I recommend you to buy one more Intel Quad Xeon E5462 2.8 GHz (+heatsink), with excatly the same CPU stepping (it should be SLANT, check it) as one you already have and save some money.
 
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Hallo,

I was looking for the same informations.
If the PSU is the same for all the 2008 models it should also handle the power required by 3,2 ghz processors.
The problem is related to heatsinks because the repair manual reports that 3,2 ghz uses a special coating to dissipate the heat:
The Mac Pro (Early 2008 Dual 3.2 GHz) computer uses a special coating on the processor heatsink and processor to manage the temperature in the computer. The silver-colored coating comes applied to the underside of the heatsink and the top of the processor.
Click to expand...
So you shouldn't use the standard 2,8 ghz heatsinks for 3,2 ghz processors.

On ebay you can easily find matched pairs of 3,0 ghz processors. If you don't mind spending a few bucks more I would upgrade both processors too.
 
The 3.2 gHz CPUs are a potential issue because of heat, not power draw. TDP of the 3.2 is 130 whereas the TDP of the 2.8 or 3.0 is only 80.

That being said, there are folks who have installed dual 3.2 gHz CPUs without issues.

The heat sinks are the same across the board. Nothing to worry about there. And there is no need to worry about finding special thermal paste either, as people who have successfully done the 3.2s used Arctic Silver or MX-4. One person even reported lower temps after the install because the old thermal paste had been breaking down after 6 years.

Depending on your own hardware setup, you may not be comfortable with the extra heat thrown off by the 3.2s. Or the fans may run earlier and longer. In my own case, I upgraded a dual 2.8 to a dual 3.0 and left well enough alone, but I have always been a nervous Nellie about the damage that excessive heat can do to components.

These issues are all discussed in detail in previous threads. Go do some reading and you can make an informed decision.
 
I have a dual 3.2GHz 3,1 & my wife has a dual 2.8GHz & performance in real life is indistinguishable. The theoretical extra 12.5% CPU performance is irrelevant compared to the SSD & GTX570 upgrades that each machine has. I really wouldn't bother with upgrading to 3.2GHz (mine was an original BTO system).
 
hey guys thank you all for the great advice on this one - i think in the end (due to small budget at the moment - should I simply the match the card that it came with for the second cpu? its the 2.8 ghz quad core xeon. thanks!

Also - finding it hard to find which heatsink I need and where to find it...
 
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The CPUs for the 2008 are old enough now that the price differences are negligible. Pair of 3.0 would runaround 100, pair of 3.2 maybe 150. I bet a pair of 2.8 would only be 50-75. If all you want is to add a 2nd 2.8, then yeah maybe 30-40 for one? Just ballpark estimate.
 
Bunking said:
hey guys thank you all for the great advice on this one - i think in the end (due to small budget at the moment - should I simply the match the card that it came with for the second cpu? its the 2.8 ghz quad core xeon. thanks!

Also - finding it hard to find which heatsink I need and where to find it...
Click to expand...

Look for part # 076-1303
 
I put a couple of 3.2s in mine, never had any trouble.

We actually got lucky, sort of.

There is a faster CPU, but since it isn't in Apple's microcode, we don't end up competing for top notch, 2nd tier much cheaper.
 
How hard do the fans run with 3.2 gHz installed? I strongly considered them but ultimately went with a pair of 3.0s.
 
flehman said:
How hard do the fans run with 3.2 gHz installed? I strongly considered them but ultimately went with a pair of 3.0s.
Click to expand...
Most of the time my 3.2GHz octo-core is quieter than my wife's 2.8GHz octo-core as her graphics card is a little noisier. When rendering video out of Premiere Pro & all 8 cores are pegged at 100% the fans on the 3.2GHz run quite a lot faster & noisier than those on the 2.8GHz.
 
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