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.

Dumb luck

…trashed my power supply. I swear it was fully insulated! Perhaps third time's a charm? We'll see after I get my first paycheck from my summer internship.

It's too bad that unintentionally tipping the G5 caused a spark and took out the fuse of the outlet by which it was powered.

Disassembling the machine and opening up the power supply revealed no burn marks or blown traces. However, the multimeter read infinite resistance over the fuse. How am I supposed to interpret these results?

gg no re (for now), as they say.

In other news, I may as well give up on hackintoshing the SR-2; I am feeling pretty convinced that OS X is not the way to go with high performance computing…and photography post production. Will I be saying hello to Windows?

SR-2 Adventures, Part II

So after hauling the SR-2 back across campus (if you ever run into a girl carrying large wads of aluminum with Apple logos on them, that's me!), I removed the system from the case mod and tested it. This was something that had to be done as soon as possible because Bayley blew up one of his processors and the return window would expire later that week -- the recommended procedure is to test the processors under high load to detect for defective samples.

I ran the processors at full load with the full 24GiB of memory with LinX, a benchmark wrapper for LinPack, the de facto Linear Algebra system. After a continuous 72hr run, the processors were fine, albeit a little toasty. I stopped worrying about them.

At this point, there were two things to be completed: the power supply mod into the G5 power supply enclosure and the rear IO panel. Although the power supply mod was not documented as much, it was the easier of the two tasks because I did not have the parts handy for the rear IO panel.

The power supply mod works as follows. Since the G5's original proprietary power supply was enclosed in a 1U-esque case, I had to replace its internals with an ATX power supply, specifically a Corsair 850W semi-modular unit.

To cut the chase, I blew up my power supply when it accidentally hit an exposed standoff and thus shorted itself to death. How did I know? When Bayley plugged it in for me (because I'm that big of a scaredy-cat), it sparked and buzzed. On my second try, I covered the entire enclosure with nonconductive tape. All was well.

Unfortunately, that was all I got done before I left MIT (yes, tooling a bit harder this term did yield better grades). As I rushed to pack for my journey back to NJ, I forgot several pieces of equipment, leading to some impulse Amazon buys: a USB header, a PS2 to USB adapter, and a USB to Ethernet. Furthermore, I also forgot an IEC cord, but I forgot to buy it on Amazon. It turns out that not many things around the house use IEC cables, but I eventually found one lurking in the kitchen. I plugged it in, and voilà!

The setup.

System profiler.

It's Here.

I present to you, fellow readers of this blog, the soon-to-be second fastest^[1] student owned computer on MIT campus:

The beginning of an ultimate case mod for the ultimate hackintosh

Projected specifications:

• Two Intel Xeon X5650 @ 4.0GHz
• 24GiB DDR3-1600 RAM
• Two AMD Radeon HD 6870

[1] The fastest will most certainly be this baby, if not for beefier GPU hardware then the soon-to-be liquid nitrogen pots sitting on top of the dual hexes. I also need to mention Cyril Lan's rig, which is powered by a 2500K @ 4.8GHz with dual AMD Radeon HD 7970s, but for most nonspecialized applications, CPUs dominate, sadly.

24GiB RAM Put to Good Use

And this means I probably will pursue videography / video post-production as hobby. Thanks Apple!

And, for nostalgia, this is the video that got me interested (yep, eight good years ago):