Is there any specific optimization in NVDEC?

Hi guys,

I am trying to use NVDEC to decode H264 video frame (1920*1080) encoded by OpenH264 , but found the performance is worse than OpenH264 decoder:
NVDEC spent 5-6 ms to decode a frame, while OpenH264 spent 4-5 ms to decode a frame.

But when I tried to use NVDEC to decode H264 video frame (1920*1080) encoded by NVENC, performance is much better:
NVDEC spent 1-1.5 ms to decode a frame, while OpenH264 spent 2-2.5 ms to decode it.

I’m wondering:

  1. Does NVENC have any specific optimization comparing to OpenH264?
  2. Does NVDEC have any specific optimization for frame encoded by NVENC?

Thanks!

BTW, PCIE link width is 8x in my machine, but I could not find place to configure it to be 16x for NVDEC optimization in Bios in Alienware Aurora R7,
any suggestion to hack it?