You can swap CPUs in the Nehalems?

[snouter]

http://www.anandtech.com/weblog/showpost.aspx?i=603

Nehalem Mac Pro: Upgrading CPUs

I actually finished testing the new Nehalem based Mac Pro several weeks ago, but in keeping up with tradition I had to see if it was possible to upgrade the CPUs on the new Mac Pro.

Indeed it is, but it’s a bit more complicated than you’d think.

Apple makes two models of the Mac Pro, one with two sockets and one with only a single LGA-1366 socket. The two socket model, often referred to as the 8-core Mac Pro, actually uses Nehalem CPUs without any heatspreaders. I suspect this is to enable them to run at their more aggressive turbo modes more frequently (high end Xeons can turbo up to higher frequencies than regular Xeons or the Core i7). The single socket model uses standard Xeons with heatspreaders, so there’s nothing special there.

I actually managed to kill a processor card doing the CPU swap but I’ve taken the hit so you all don’t have to It’ll all be included in the article, I’m simply waiting on a replacement heatsink since an integrated thermal sensor got damaged during the initial swap. For now just know that it is possible to upgrade the CPUs in these things and it’s not too difficult to, you just need to know what to expect and to be patient.

If you’re on the fence of buying today, opt for the slower CPUs and upgrade later if you’d like. And if you already have a good Mac Pro and aren’t terribly CPU bound, save the money and buy SSDs instead - in many cases the performance improvement is far greater. Once again, I’ll address all of this in the article itself.

 

[Pressure]

Does this really come as a surprise?

What surprised me, however, is that the 8-core has it's precious Nehalem cores fully exposed and not protected by a heatspreader.

 

[snouter]

Does this really come as a surprise?

What surprised me, however, is that the 8-core has it's r´precious Nehalem cores fully exposed and not protected by a heatspreader.

I am a little surprised? Apple has not always supported upgradeable CPUs.

First time I've actually read that it is possible, repeatable, doable, etc.

 

[nanofrog]

Does this really come as a surprise?

What surprised me, however, is that the 8-core has it's r´precious Nehalem cores fully exposed and not protected by a heatspreader.

Sometimes the addition of TIM and the heat spreader lower the amount of heat that can be drawn away.

You end up with die,TIM, metal, TIM, metal on the heat sink. TIM though thermally conductive, isn't that wonderful compared to the copper and/or other metals used in the heat sink. Multiple layers, or too thick of a single layer, can become more of an insulator. Sort of like a blanket.

So the elimination of these layers were needed to maximize thermal transfer.

 

[Pressure]

I am a little surprised? Apple has not always supported upgradeable CPUs.

First time I've actually read that it is possible, repeatable, doable, etc.

You have been able to change processors for a very long time. Just take the Power Mac as an example.

Sometimes the addition of TIM and the heat spreader lower the amount of heat that can be drawn away.

You end up with die,TIM, metal, TIM, metal on the heat sink. TIM though thermally conductive, isn't that wonderful compared to the copper and/or other metals used in the heat sink. Multiple layers, or too thick of a single layer, can become more of an insulator. Sort of like a blanket.

So the elimination of these layers were needed to maximize thermal transfer.

Well, if I have to get pedantic the heatspreader actually helps dissipate heat because it disperses the heat over a larger area. Of course large amounts of goo can have an adverse effect but hardly the case when looking at the force required to mount modern heatsinks.

Every desktop processor from Intel since the Pentium 4 (NetBurst) have had heatspreaders on them. That is why I find it surprising.

 

[tobyg]

I'm not surprised, as other forum members have already found out all of this information quite a while ago. Nothing new to read in this thread, if you've kept up with the previous threads in this forum.

Nothing against the OP of course, just saying that Anandtech isn't giving us any info here that wasn't already in this forum.

 

[snouter]

You have been able to change processors for a very long time. Just take the Power Mac as an example.

I know, I have a 9500 132 in the closet that I once upgraded to a dual 604e 180MHz and eventually a G3 400MHz.

Just not sure how they've been handling it lately. Good to hear.

Nothing against the OP of course, just saying that Anandtech isn't giving us any info here that wasn't already in this forum.

I feel ya. I'm new and there's only so much searching and browsing you can do. I've read the last month or so and didn't see anything conclusive on it.

 

[nanofrog]

Well, if I have to get pedantic the heatspreader actually helps dissipate heat because it disperses the heat over a larger area. Of course large amounts of goo can have an adverse effect but hardly the case when looking at the force required to mount modern heatsinks.

I'd have to go back and check, but IIRC, the dies are large enough, there's not much additional surface area to dissipate the heat over via the heat spreader. In such a case, the better thermal contact with the die surface to the cooler may make more sense. Hopefully, which ever way a vendor chooses to go, it's based on test data.

To me, the mounts have varied. Not so much by what was on the board, but the mounting bracket design used with a specific cooler. And on occasion, the cooler's mounting surface was processed poorly (uneven, or too rough). These gave me the impression they were trying to get them made and shipped in a hurry.

Every desktop processor from Intel since the Pentium 4 (NetBurst) have had heatspreaders on them. That is why I find it surprising.

I have in a few HP's.