Laptop GPU (NVENC) vs CPU x264 for encoding:

[kavinreed]

For those who encode a lot on laptops, do you still prefer CPU x264/x265 for quality, or is NVENC on newer GPUs good enough now? I know NVENC is much faster, but I'm not sure how visible the quality gap is at the same bitrate these days.

Also wondering if a laptop with a dedicated GPU is really worth it for encoding, or if a good CPU with more cores is the better use of money.

[jagabo]

Laptops are notoriously under-cooled and should be avoided for software encoding.

[pandy]

Same bitrate? This will not work but if you can accept 20% higher bitrate then NVEnc is sane choice.

[jagabo]

I use x264 for 8bit h.264 SD and HD encoding, NVEnc for 10 bit h.265 UHD encoding. Using a well cooled desktop computer.

[kavinreed]

Thanks, the 20% bitrate rule of thumb and the split by format are really useful. On the cooling point, does that apply to NVENC as much, since it uses the dedicated encoder block instead of loading the CPU cores? Or do laptops still throttle enough during long encodes to matter?

[jagabo]

Early Nvidia GPU h.264 encoding required as much as 2x the bitrate. I think 20% more bitrate isn't enough, even for the current hardware -- at lease for h.264 encoding. I'd put it closer to 50%. And AMD GPU encoding is far worse than Nvidia.

[pandy]

Thanks, the 20% bitrate rule of thumb and the split by format are really useful. On the cooling point, does that apply to NVENC as much, since it uses the dedicated encoder block instead of loading the CPU cores? Or do laptops still throttle enough during long encodes to matter?

As jagabo says - take 20% figure with some bit of salt - it will be highly dependent on content nature.
Hardware encoders use fraction of power consumed by CPU so this should not impact severely on produced heat.