Benchmark Results: CPU Utilization
Objective testing turns out to be a lot more difficult than we might have first hoped. The problem is that none of the software involved is designed to allow hardware acceleration to be disabled. Turning off GeForce hardware acceleration in PowerDVD has no effect, and the program appears to continue to lean on Nvidia's VP4 engine for MVC decoding.
We can extract some useful data from these test systems anyway, because the GeForce GT 240 card in the HTPC is essentially identical to the GeForce GT 240 in the test system we put together. This gives us a great opportunity to test the CPU utilization on different CPUs when using similar graphics hardware:
A you can see, the dual-core Pentium G6950 demonstrates an average CPU utilization of just under 20% during Blu-ray 3D playback when a GeForce GT 240 is handling decode acceleration. On our Core i7-920, CPU utilization appears to be about half of that, or just under 10%.
Now, we might not be able to turn off hardware acceleration, but we can try things out with a card that doesn't support Blu-ray 3D's MVC codec. Here's how the GeForce GT 240 (a card with Blu-ray 3D-decode acceleration) compares with a GeForce GTX 260 (a card without Blu-ray 3D decode acceleration) on our Core i7-equipped test machine:
There is certainly a dramatic increase in CPU utilization here, from just under 10% with the GT 240 to about two and a half times that with the GeForce GTX 260.
With the Core i7 CPU under 30% of load, we can tell more CPU power is required, but the i7 is far from its limits. The question remains: how much CPU do you need for a graphics card that doesn't support MVC decoding?
We put together an Athlon II system for testing. The system allowed us to put quad and triple-core Athlon II CPU software decoding to the test. However, we couldn't get a dual-core CPU to play back Blu-ray 3D on our test system. Here are the results:
As you can see, the triple-core Athlon II X3 440 at 3 GHz is highly stressed during Blu-ray 3D playback. It's difficult to make precise conclusions without per-core utilization data but CyberLink's software decoder appears to take advantage of threading, a feature that quad-core owners will appreciate. Judging from the performance we've seen, we think Blu-ray 3D can be comfortably played back with a triple-core CPU at 3 GHz or a quad-core CPU at 2.5 GHz using PowerDVD's software decoder.