|AMD Phenom-II X6-1100T CPU HDE00ZFBRBOX|
|Reviews - Featured Reviews: Processors|
|Written by David Ramsey|
|Tuesday, 07 December 2010|
Page 12 of 14
AMD Black Edition CPU Overclocking
Like the 1090T Black Edition and 965 Black Edition, the 1100T has an unlocked multiplier, so while you can overclock it in the classic fashion by increasing the core frequency (which ASUS calls the "CPU Bus Frequency"), it's easier to simply increase the multiplier. Although the processor seemed to run stably at 4.2GHz (achieved with a multiplier of 21) with the voltage set to 1.5V, it wouldn't complete the SPECapc Lightwave benchmark at this setting (after three attempts), so after several tries at some dangerously high voltages, I was forced to drop the multiplier to 20.5 for a final speed of 4.1GHz with a 0.1875 overvolt. I always disable auto-overclocking features like Turbo Core when I overclock, since I'm trying to reach the highest frequency all cores can sustain and don't want a system suddenly crashing when the CPU tries to crank things up a few hundred MHz. For cooling, I used a CoolIT Systems ECO A.L.C. Eco-R120 CPU cooler.
AMD's Turbo Core feature works so well that even enthusiasts may wish to consider if overclocking a Thuban-core CPU is worth the extra energy and cooling required. In several of the benchmarks in this review you'll notice very little difference between the scores returned by the stock-clocked and overclocked 1100T. The reason is that if the benchmark uses three or fewer of the six available CPU cores, the cores will be running at up to 3.7GHz, which is less than 10% slower than 4.1GHz. Since the CPU can dynamically vary the clock speed of the cores as the computational load changes, the processor will run at its most efficient settings in most cases, only cranking things up when it's needed. For applications that actually stress all six processor cores, you can expect performance to increase almost linearly with clock speed, but since few applications do this, you might just want to let Turbo Core handle this for you. The overclock certainly won't make any difference in gaming.
If you've read Benchmark Reviews' previous coverage of the AMD Phenom-II X6-1075T Processor and the AMD Phenom-II X6-1090T processor, you'll see the 4.1GHz overclock achieved with the AMD Phenom-II X6-1100T Black Edition processor is very close to the 4.155GHz reached with the 1075T and the 4.0GHz (with Turbo Core enabled) reached with the 1090T Black Edition. At the time of this writing, the Newegg prices for these three processors are:
Now, there's never a guarantee that any given Thuban-series processor will reach the same overclocks I did (and if you're overclocking a non-Black Edition CPU like the 1075T, you'll need a good quality motherboard and RAM to hit the highest overclocks), but I'd be very surprised if you couldn't at least reach 3.9GHz or 4.0GHz on any hexacore AMD CPU. That being the case, there's no reason to spend more money for the 1100T Black Edition when its $70-cheaper sibling 1090T Black Edition is just as fast, and the $100-cheaper 1075T can be just as fast if you're using a good-quality AMD 800-series motherboard like the ASUS Crosshair IV Extreme I used in this review. Even with all CPUs running at their stock clock speeds, you'll notice very little difference in most benchmarks. Still, the whole point of overclocking (originally, anyway) was to make a less-expensive part perform like a more expensive part, and the overclocked AMD Phenom-II X6-1100T Black Edition provides most of the performance of the much more expensive Intel Core i7-980x Extreme, as I'll show in the next section where I'll explain my conclusions.