How do you upgrade the processors in the "Original/Early 2008" Mac Pro models? How are the processors mounted?

Please note that this answer specifically refers to the original Mac Pro that was discontinued on January 8, 2008 and replaced by the "Early 2008" models. However, the "Early 2008" Mac Pro models also use LGA 771 sockets, and it is physically possible to replace the processors in a similar manner.

Officially, Apple provides no public information regarding whether or not it is possible to upgrade or replace the processors in the Mac Pro models.

However, the processors in the original Mac Pro are mounted on 771-pin LGA Sockets and the not for public distribution Apple Service Manual confirms that the processors can be replaced.

Compared to upgrading the memory or hard drives, replacing the processors is complicated, no doubt violates the warranty if performed by an end user, and consequently is not recommended by EveryMac.com.

Regardless, Apple roughly provides the following instructions for authorized service personnel to replace the processors:

1. Backup all data on the Mac Pro and verify that the backup is successful.

2. Shut down the Mac Pro, unplug it, and disconnect any cords or cables.

3. Prior to opening the case and laying it on its side with the access side facing up, Apple mentions that service personnel may find a "flat-blade screwdriver helpful in releasing the processor holder latch" and notes that:

Every time you remove a processor, you must replace the thermal grease on the processor heatsink. New grease and alcohol wipes for removing the previous grease are included with replacement processors. Instructions for applying the grease are included with the processor heatsinks procedure.

4. Before one can even access the processors, the following components have to be removed:

• Hard drives in drive bays 1 and 2
• Any 12-inch PCI Express cards
• PCI Express card installed in slot 1
• Top and bottom memory cards
• Processor heatsink cover
• Front fan assembly
• Processor heatsinks
• Memory cage

Apple provides authorized service personnel with instructions for removing each of those components as well.

5. Release the processor holder latch on each processor to be replaced (see below). This is where the flat-blade screwdriver may come in handy.

Photo Credit: Site sponsor PowerMax. In this photo, the processor holder door for CPU A is closed (top) and CPU B is open (bottom). The processors have been removed. PowerMax also provides a number of other photos that you may find helpful when upgrading internal components.

6. Service personnel are then instructed to "rotate the top of the holder to the open position" and "lift the processor out of the holder".

7. When installing the new processor, Apple warns:

When removing or installing a processor, always hold the processor by the edges. Be extremely careful not to touch the gold pins on the bottom of the processor, as this type of connector is very sensitive to contamination. Also be careful not to touch the gold pins in the processor socket on the logic board.

8. Remove the protective cap covering the replacement processor's pins, align the processor "notch" with the "tab on the processor holder", place the processor in the socket, close the "door", and close the processor holder latch as well.

9. Before reinstalling the heatsinks, Apple reminds service personnel to "make sure the two logic board bumpers by the upper processor are in place."

At the time the Mac Pro was introduced, EveryMac.com was concerned that Apple might have blocked processor upgrades through firmware to avoid cutting into future hardware sales. However, EveryMac.com was optimistic that because the company did not restrict those interested in upgrading the processor in the Intel iMac or Mac mini systems -- prior to the "Early 2009" models -- it likewise would not impose restrictions on the Mac Pro.

In an in-depth review of the original Mac Pro from the always excellent AnandTech -- the author concurred that "it wouldn't be too far fetched to think that you could swap a pair of Clovertowns in these systems with no more than a firmware update".

A few months later -- but prior to the release of the build-to-order Mac Pro with two 3.0 GHz "Quad Core" Xeon X5365 (Clovertown) processors on April 4, 2007 -- AnandTech got their hands on engineering samples of pre-release Intel "Clovertown" processors, and the author reported that:

We grabbed a pair of 2.4 GHz Clovertown samples and tossed them in the system, and to our pleasure, they worked just fine. Our samples used a 1066 MHz FSB, although we're expecting the final chip to use a 1333 MHz FSB, but the most important part of the test is that all 8 cores were detected and functional.

A helpful Italian Mac user even posted a step-by-step guide to upgrading the processors in the original Mac Pro.

To purchase a new or used Mac Pro, free of sales tax, please visit PowerMax.

Also see:

• How do you upgrade the processors in the "Early 2009" Mac Pro models? How are the processors mounted?
• How do you upgrade the processors in the "Mid-2010" Mac Pro models? How are the processors mounted?