|AMD Phenom-II X6-1100T CPU HDE00ZFBRBOX|
|Reviews - Featured Reviews: Processors|
|Written by David Ramsey|
|Tuesday, 07 December 2010|
Page 11 of 14
Video Transcoding Tests
Few consumer applications will make good use of a six-core processor, or even a four-core processor. Extra cores can give you a system that remains responsive when performing a computationally-intensive background task, but will rarely accelerate the execution of an individual program. There are several reasons for this:
All that said, media transcoding (converting to a different format) is something that does scale well with the number of available cores, and the free and open-source Handbrake 0.94 video transcoder is an example of a program that makes full use of the computational resources available. For this test I used Handbrake 0.94 to transcode a standard-definition episode of Family Guy to the "iPhone & iPod Touch" presets, and recorded the total time (in seconds) it took to transcode the video.
Here we finally see a real-world program that can fully utilize multi-core CPUs. The results scale nicely with both clock speed and the number of available cores. The AMD processors do themselves proud, with every six-core AMD chip beating every four-core Intel chip. Note, however, that the four-core AMD 965 Black Edition is only very slightly faster than the Core i5-750 and slower than the Core i7-930. The overclocked AMD Phenom-II X6-1100T edges just ahead of the stock-clocked Intel Core i7-980x. One might ask why the 980X didn't do better, since its Hyper-Threading feature gives it 12 virtual cores, and the answer is simply that a virtual core is an abstract construct wherein the processor tries to schedule code to make the best use of available execution units; it's not the same as a real extra core. The results depend on the task and the code, and Handbrake code just doesn't benefit much from Hyper-Threading.
You can compare the bang-for-the-buck performance of these CPUs in Handbrake 0.94 by making a "dollars per reciprocal second" measurement: in other words, we're looking for the best combination of low processor price and low encoding times.
The 1075T wins this comparison, beating the overclocked AMD Phenom-II X6-1100t Black Edition. It's telling that only one of the AMD processors exceeds 400, while none of the Intel processors are under 400. In this calculation, the AMD 1075T is 3.9 times "better" than the 980X, which is reasonably close to the 980X's 5x-more-expensive price differential. The 1090T and 1075T are the easy winners in this admittedly ad hoc bang-for-the-buck measurement.
x264 HD Benchmark 3.19
Tech ARP's x264 HD Benchmark comprises the Avisynth video scripting engine, an x264 encoder, a sample 720P video file, and a script file that actually runs the benchmark. The script invokes four two-pass encoding runs and reports the average frames per second encoded as a result. The script file is a simple batch file, so you could edit the encoding parameters if you were interested, although your results wouldn't then be comparable to others.
The AMD hexacore processors maintain their lead over the Intel processors (other than the 980x) here, although the lead is much slimmer than it was with Handbrake, and the extra cores don't seem to improve performance as much as they do with Handbrake. In the Handbrake test, the AMD 1075T six-core processor finished in 22% less time than the four-core AMD 965, but in this test the difference is only about 2%. Of course, "seconds to encode video file" isn't directly comparable to "average frames per second", but I still expected more differences here.
For runs 3 and 4, the differences between processors are much larger. The Intel Core i5-750 and Core i7-930 manage to just squeak by the AMD 965 Black Edition, and the performance scaling with clock frequency and cores is smooth and regular.