Why not use GPU fully when generating optimized media?

As you can see in the screenshot, the GPU is only used to about 25% of its potential when creating optimized media. I am using CUDA with a 1080ti.

Screen Shot 2018-08-09 at 11.55.23.png (75.67 KiB) Viewed 724 times

Is there a reason for it?

That’s a CPU job. See what they are doing. Plus, your media should be fast.

So, what's the GPU doing at 25-30%?
It's reading/writing at about 70–80 Mb/s. The media is way faster, capable of 500 Mb/s read/write.

For example debayering if your source is RAW.
All intermediate codecs are CPU based for decoding/encoding.
Your CPU is "nicely busy" so all looks good.

I see, thank you for the explanation!