Lowest-power Hardware Accelerator

Hi, I have a Windows 8 tablet and K-Lite with LAV video decoder. Which uses the least power, DXVA2 or QuickSync? Thanks.

DXVA2 native is the best choice

Thanks, Admin, I suspected DXVA2 was best, since I found it to use far less CPU. I'd like to understand why DXVA2 is better, though. It obviously uses less CPU, since it's a GPU application, but could the extra CPU cycles used by QuickSync be somehow more power-efficient than software-only decoding?

Quicksync performs similar to dxva2 copy-back. Copy-back means the data is moved from GPU memory to CPU memory. That step is usually not needed, and native mode skips it to get better performance.

I understand now. Thanks for making it clear, Admin.

I just tested and found that DXVA2 Native has about 1/4 the CPU load of QuickSync.

So is nVidia cuvid similar to dxva2 copyback too?
Should I use dxva2 native instead of nVidia cuvid.

I'm using gt640 with windows 7

Yes, CUVID also performs a copy-back operation. DXVA2 is recommend.