SR-2 Adventures, Part III

I recently ordered a third power supply (don't worry, I'm not modding this one!) for my hackintosh. It's a server grade unit rated at 1200W made by PC Power & Cooling, which should be sufficient for further upgrades, such as dual Nvidia GTX 580s (for raytracing, of course). At first, 1200W seems gluttonous, but we note that overclocked processors can consume up to 200W, since power is approximately proportional to clock speed squared.

Now onto the fun part: overclocking! Recall that this system uses two Intel Xeon X5650-like [1] chips sourced from eBay. To get up to 4GHz, we use the following voltages:

• Disable Vdroop
• Set Vcore to 1.35
• Set Vtt to 1.35
• Set DIMM to 1.65
• V_IOH to 1.40

Then in the signal tweaks menu:

• Set QPI0 to -86
• Set QPI1 to -16

Then jiggle the settings in the CPU menu:

• Enable Speedstep
• Enable Turbo
• Disable C-state

Note that enabling Turbo will get you a 21x multiplier, or so people say. Finally set BCLK to 191 and voilà, a 4GHz 12-core monster! Sadly OS X does not notice the turbo multiplier at 21x, so it won't show 4GHz in System Profiler. In any case, here's a screenshot of the system at 191x21:

Issues

Mac App Store can't verify computer

This one is annoying. I haven't bothered to fix the issue for this hackintosh (I did it for my single processor computer), but the solution involves deleting the network interfaces file, rebooting, and readding the interfaces in System Preferences. I will update this section once I fix the issue.

Flaky PS2-USB adapter

For BCLKs @ 195 and 200 I noticed that my keyboard would work for about 10 seconds after being plugged in and then it would stop working. I check the Console, which says

IOUSBPipe:ClosePipe for address, ep 1 had a retain count > 1. Leaking a pipe
IOUSBPipe:ClosePipe for address, ep 2 had a retain count > 1. Leaking a pipe

I am convinced that this is due to the overclock being unstable. The problem goes away when I'm running at 190 or 191. I also noticed that USB mouse and ethernet adapter aren't flaky at all, but my USB headset does develop crackling noises after a short while (under 10 min).

It's heating up my room!

Yep, sadly this rig is overpowering the air conditioner in my residence. I can feel it spewing hot air out the back. :(

[1] Duck test, but for CPUs: If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.