Lab Tested: AMD's Bulldozer Packs Plenty Of Cores, But Not Enough Power

Testing: Video Transcoding and Energy Efficiency

Thus far we haven’t seen much to write home about. The FX-8150 maintains a solid pace alongside the Core i5-2500K, but neither part seems to outshines the other.

Things get a bit more interesting when we turn our attention to to media transcoding. This is a fairly common task: You’ve got a an audio or video file, and you’d like to convert it into another format. For my test case, I grabbed a copy of Big Buck Bunny, an open-licensed animated film that’s available in a wide variety of formats and resolutions. There are plenty of software options to choose from; I went with Arcsoft’s Media Converter.

There are a number of hardware acceleration technologies available: Nvidia offers CUDA, AMD offers Stream, and Intel offers Quick Sync on platforms using its integrated graphics. For parity’s sake I chose AMD Stream, as my test benches are equipped with that Radeon HD 6970. AMD Stream (and the other technologies I mentioned) allow a system’s graphics card to work with the CPU to churn through transcoding a bit faster.

For this test, I converted a 1080p version of Big Buck Bunny down to an iPad-friendly 720p resolution. These results are a bit more clear cut: after multiple passes, the FX-8150 completed its conversion with an average time of 3 minutes and 19 seconds. The Core i5-2500K finished a full minute faster, at 2 minutes and 18 seconds.

What happens when we shut those GPUs off and let the processors stand on their own merits? The same: 4 minutes and 22 seconds for the FX-8150, 2 minutes and 58 seconds for the Core i5-2500K.

The last measure to consider is power efficiency. I tested two scenarios using a power meter. For the idle setting, I let the machine sit at the desktop. To test power consumption while under a heavy load, I ran a pass of the Crysis 2 benchmark at maximum settings, and let the power meter record the results.

The results are fairly cut and dry here, too. While sitting idly, the Core i5-2500K test bench drew 71.8 watts of power. The FX-8150 drew 109.8. When under load, the Core i5-2500K climbed up to 300 watts, while the FX-8150 peaked at 356 watts.

That’s a fairly dramatic difference, but one that’s plausible. Both processors are 32nm parts, but the Core i5-2500K has a max TDP of 95W, while the FX-8150 has a max TDP of 125W — it’s simply a hungrier part. There are also the 8 physical cores to consider; the Core i5-2500K has 4, with 8 virtual cores thanks to hyper-threading. One could also make a case for optimization: the hardware I tested is likely to see plenty of BIOS improvements as it progresses, so I won’t be surprised if motherboard updates pull those numbers down a bit with time.

But in the end, we’re still looking at a brand new processor that draws a significant chunk of energy to generate performance that barely keeps pace with Intel’s 9-month old hardware.

Next: Overclocking...

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