Tag Archives: AMD Phenom II X6 1100T

F@H Efficiency: Overclock or Undervolt?

Efficiency Tweaking

After reading my last post about the AMD Phenom II X6 1100T’s performance and efficiency, you might be wondering if anything can be done to further improve this system’s energy efficiency.  The answer is yes, of course!  The 1100T is the top-end Phenom II processor, and is unlocked to allow tweaking to your heart’s content.  Normal people push these processors higher in frequency, which causes them to need more voltage and use more power.  While that is a valid tactic for gaining more raw points per day, I wondered if the extra points would be offset by a non-proportional increase in power consumption.  How is efficiency related to clock speed and voltage?  My aim here is to show you how you can improve your PPD/Watt by adjusting these settings.  By increasing the efficiency of your processor, you can reduce the guilt you feel about killing the planet with your cancer-fighting computer.  Note that the following method can be applied to any CPU/motherboard combo that allows you to adjust clock frequencies and voltages in the BIOS.  If you built your folding rig from scratch, you are in luck, because most custom PCs allow this sort of BIOS fun.  If you are using your dad’s stock Dell, you’re probably out of luck.

AMD Phenom II X6: Efficiency Improved through Undervolting

The baseline stats for the X6 Phenom 1100T are 3.3 GHz core speed with 2000 MHz HyperTransport and Northbridge clocks. This is achieved with the CPU operating at 1.375v, with a rated TDP (max power consumption) of 125 watts. Running the V7 Client in SMP-6 with my pass key, I saw roughly 12K ppd on A3 work units.  This is what was documented in my blog post from last time.

Now for the fun part.  Since this is a Black Edition processor from AMD, the voltages, base frequencies, and multipliers are all adjustable in the system BIOS (assuming your motherboard isn’t a piece of junk).  So, off I went to tweak the numbers.  I let the system “soak” at each setting in order to establish a consistent PPD baseline.  I got my PPD numbers by verifying what the client was reporting with the online statistics reporting.  Wattage numbers come from my trusty P3 Kill-A-Watt meter.

First, I tried overclocking the processor.  I upped the voltage as necessary to keep it stable (stable = folding overnight with no errors in F@H or my standard benchmark tests).  It was soon clear that from an efficiency standpoint, overclocking wasn’t really the way to go.  So, then I went the other way, and took a bit of clock speed and voltage out.

F@H Efficiency Curve: AMD Phenom II X6 1100T

F@H Efficiency Curve: AMD Phenom II X6 1100T

These results are very interesting.  Overclocking does indeed produce more points per day, but to go to higher frequencies required so much voltage that the power consumption went up even more, resulting in reduced efficiency.  However, a slight sacrifice of raw PPD performance allowed the 1100T to be stable at 1.225 volts, which caused a marked improvement in efficiency.  With a little more experimenting on the underclocking / undervolting side of things, I bet I could have got this CPU to almost 100 PPD / Watt!

Conclusion

PPD/Watt efficiency went up by about 30% for the Phenom II X6 1100T, just by tweaking some settings in the BIOS.  Optimizing core speed and voltage for efficiency should work for any CPU (or even graphics card, if your card has adjustable voltage).  If you care about the planet, try undervolting / underclocking your hardware slightly.  It will run cooler, quieter, and will likely last longer, in addition to doing more science for a given amount of electricity.

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F@H Efficiency: AMD Phenom X6 1100T

Welcome back to the fold!  In the last post, I showed how increasing the # of CPU cores has a massive positive impact on the amount of cancer-fighting research your computer does, as well as how efficiently it does it.  In stock form, the quad core Intel Q6600 delivered just shy of 6000 points per day of F@H with all 4 cores engaged.  My computer’s total power draw at the wall was 169 watts.  So, that works out to be 6000 PPD / 169 Watts = 35 PPD/Watt.  Not too bad, considering the horrible efficiency numbers of the uniprocessor client.

In this article, I’m jumping forward in time to a more modern processor…the AMD Phenom II X6 1000T.  This six-core beast is the last of the true core-for-core chips from AMD (Bulldozer and newer CPUs have 2 integer units but only 1 floating point unit per core).  With 6 physical floating point cores, the AMD 1100T should be good at folding.

Note that I am obviously using a completely different computer setup here than in the last post (I have an AMD machine and an Intel machine).  So, the efficiency numbers aren’t a perfect apples-to-apples comparison, due to the different supporting parts in both computers.  However, the difference between processors is so large that the differences in the host computers really doesn’t matter.  The newer AMD chip is much better, and that is what is driving the results!

Test Rig Specs:

AMD Phenom II X6 1100T
Gigabyte GA-880GMA-USB3 Micro ATX Motherboard
8 GB Kingston ValueRam DDR3 1333 MHz (4 x 2GB)
Seasonic S12 II 380W 80+ PSU
Hitachi 80 G SATA Hard Drive
Linkworld MicroATX
Fans: 2 x 80mm Side Intake, 1 x 80mm front intake, 1 x 92 mm Exhaust
Noctua NH-C12P SE14 140mm SSO CPU Cooler

A note about the operating system…

The previous tests on my Intel Q6600 were performed using Windows 7 with the V7 folding client.  Due to Windows costing money, I used Ubuntu Linux on my AMD system with the V7 folding client.  Linux is a bit more capable of maxing out a PC’s hardware than Windows, so the resulting PPD numbers are likely slightly higher than they would be had the machine been running Windows.  However, the difference is typically small (5 percent or so).  Note that over time, this performance bonus can really add up.  This is why Linux is the preferred operating system for many dedicated Folding at Home users.

AMD Folding Rig - Phenom II X6 Configuration

AMD Folding Rig – Phenom II X6 Configuration

Test Results

AMD Phemom II X6 1100T Folding at Home Performance and Efficiency

AMD Phemom II X6 1100T Folding at Home Performance and Efficiency

AMD 1100T 6-core CPU pushes the efficiency curve further

AMD 1100T 6-core CPU pushes the efficiency curve further

As expected, the 6-core 1100T is a performer when it comes to F@H.  Producing just shy of 13,000 Points Per Day with a total system power draw of 185 watts, this setup has an efficiency of 67 PPD/Watt.  This is almost twice that of the older Intel quad-cores.  Note that I am not Intel-bashing here…if you do some google searching, you will likely see that the new Intel Core I5 and I7’s do even better in both raw PPD and PPD/W than the AMD 1100T.  The moral of the story is that you should try and set up your folding Rig with the most powerful, latest-generation processor you can.  I recommend upgrading at least once a year to keep improving the performance and efficiency of your F@H contributions.  Don’t be that guy running an old-school Athlon X2 generation 300 points per day (while using 150 watts to do it).