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Ready for another nerd fest? This one’s a doosy.

Back story

About a month ago, I stumbled upon a forum post talking about upgrading the CPUs in the original Mac Pro 1,1 — the Mac Pro I have. In short, going from 2 x 2.66GHz (dual-core chips) to 2 x 2.66GHz (quad-core chips). In shorter, moving from four cores to eight. Shortest, twice the horsepower.

I’d never replaced CPUs before, and especially where the wisdom is you don’t monkey with your Mac; they’re built as they are. Holy, even. I was quite nervous in taking on this task . Lots of new things to touch and play with: CPUs (heavier than they look), thermal paste (WTF?) and a custom-made 25cm long 3mm allen key (thanks dad!).

8 cores.png


It worked. I now have an octocore Mac Pro for a modest sum and some elbow grease.

Why are you telling me this?

I want to document some things I found during the process that I didn’t find in the handful of online resources. The online guides and forum posts were a tremendous help — I wouldn’t’ve had the balls courage to go through with it, but while they documented the process thoroughly, they left out a few things which I think are important, especially to someone who’s never done something like this before. These are only observations, but they might help you if you want to beef up your original Mac Pro:

  • CPUs — The CPUs are quite heavy in relation to how they look. Be careful with them when you get them. When you’re inserting the new CPUs into your Mac, they don’t need to be pushed or ‘plugged’ in to the sockets, they kind of just sit on top of the pins. Think a flat bit of wood resting on a bed of nails. You literally drop them onto the sockets. When you do this, get as close as you can and ease one side down first, like you would close a heavy trap door. Then lower the other side down as much as you can before letting it go.

    I also gently wiggled the CPU in it’s socket before I closed the latch, to make sure it was seated properly.

    Another thing to do is pay attention to the feel and pressure of lifting the latch on the original CPUs. I didn’t do this so when I had to close the latch on the new ones I felt enough resistance that I thought I was bending the delicate pins underneath. I didn’t lift again to see if I had, but my Mac’s running so it must’ve been OK. So remember the pressure of the latch when you take out your CPUs.

  • Thermal paste — I used Arctic Silver 5 because it seemed to have a good wrap in teh interwebs. Read this PDF before you do anything with the thermal paste. This documents how to apply the thermal paste to the Xeon dual- and quad-core chips that I used in my Mac Pro upgrade.

    The most important part in the document (I think) was about ‘tinting’ the heatsink and CPU. Tinting is the process of filling up the microscopic valleys in the metal of the heatsink and CPU cover, so there is no tiny bubbles of air (which is crap at conducting heat). You do not need a lot of paste on this step, one dot a bit larger than a pin head is all that’s needed here. Seriously. With a credit card it spreads surprisingly thin. You’re going to rub most of it off again anyway so the surfaces clean. Anymore paste at this stage will be a waste.

    You should do this to your new CPUs before you seat them in the motherboard! I didn’t read the PDF correctly and I had seated my CPUs already. I didn’t want to lift them out again for fear of damaging the CPU or pins. It can be done while seated, but it’d be much easier (and safer) if you did this part while you had free access to the CPUs.

    Applying the thermal paste (after tinting) can be read about in that PDF, and should be done once the CPUs are seated, so you don’t run the risk of getting it on your fingers.

    Read that PDF again.

  • Extra long allen (hex) key — this was impossible to find in Malaysia, so I had my dad weld me one up and mail it over. This is the tool you’ll need if you can get it. Amazon wouldn’t ship to Malaysia :(

    I used a 3mm (metric) sized key, and you’ll need at least 20cm of length. Some guides say you could do it with a normal sized tool, but I wouldn’t recommend it. If you slipped you’d run the risk of damaging the fins on the heatsinks. Get the tool.

  • Set aside some time — the online guides say about an hour. I took just under two because I was being careful and methodical, and I had the time to spare.
  • Teh internets — Ensure you have some access to the internet when doing this. I had several of the guides in Safari tabs open at once, and was switching between them through the process. Teh internets eased my mind.

Take ‘er easy, Dude

These are the things you should know before you tackle the task. A man wiser than myself once said:

Don’t stress about the brain surgery. It’s more forgiving than you think.

And in retrospect, It’s a pretty straight-forward task. I just let my inexperience freak me out a little. Take your time, stick with the guides, and be mindful when digging around in the guts of your Mac Pro.

Online resources