How do you upgrade the processors in the "Early 2009/Nehalem" Mac Pro models? How are the processors mounted?

Officially, Apple does not state whether or not the processors in the "Early 2009/Nehalem" models -- the Mac Pro "Quad Core" 2.66 (2009/Nehalem) and Mac Pro "Eight Core" 2.26 (2009/Nehalem) -- can be upgraded.

However, at the time of purchase, Apple does offer the "Quad Core" model with a single 2.93 GHz Quad Core Xeon W3540 processor for US$500 more and the "Eight Core" model with dual 2.66 GHz Quad Core Xeon (X5550) processors or dual 2.93 GHz Quad Core Xeon (X5570) processors for an additional US$1400 or US$2600, respectively.

The memory and hard drives are designed to be upgraded by end-users, and doing so is quite simple, but Apple does not intend for one to upgrade their own processor(s). Upgrading the processors violates the warranty, and consequently, EveryMac.com does not recommend that one upgrade the processor(s) in a "Early 2009/Nehalem" Mac Pro themselves.

Nevertheless, the "Early 2009/Nehalem" Mac Pro models have the processors mounted on LGA sockets, and as part of a longer upgrading piece, the hardworking hackers at the always excellent AnandTech successfully upgraded the stock 2.26 GHz Quad Core Xeon E5520 processors in the "Eight Core" model with two 2.93 GHz Quad Core Xeon X5570 processors.

Photo Credit: AnandTech (Unscrewing Mac Pro Heatsink)

Essentially, one needs to slide the processor tray out of the Mac Pro, unscrew the heatsinks with a 3mm hex key, remove the heatsinks, remove the processors, install the new processors, apply thermal paste, reattach the heatsinks, reinsert the processor tray, and close up the computer.

However, it is critical to note that Apple uses custom processors without an "integrated heat spreader" and these cannot be purchased on the resale market by an individual. AnandTech instead installed processors *with* an integrated heat spreader and upon the first time reattaching the heatsinks killed one of the new processors, the Mac Pro processor board, and one of the heatsinks. This mistake cost nearly US$2000 to remedy.

Ultimately, it is quite possible for one to upgrade the stock processors in the "Early 2009/Nehalem" Mac Pro models with faster ones. However, due to the fact that Apple uses slightly different processors than those available for resale, even a highly skilled hardware hacker should proceed with extreme caution. This is most definitely not an upgrade for those with limited hardware hacking experience and is not recommended by EveryMac.com.