Quote But the video encode time is the same as my old computer. Does PowerDirector 17 support more than 4 cores?

Yes, PD17 supports more than 4 cores. Total core utilization is very dependent on encode format. Since you say same encode time, any chance you are using hardware encoding with your RX 570, if so, one would expect about equal encode times.

Jeff

Quote My old system was like this: i7 4770K processor + MSI RX 570 Graphics card ..
I bought a new computer today. This computer has a Ryzen 9 3900x processor (12 cores) and ASUS Rog Strix X570-F Motherboard.
I use the same video card on my new computer.
But the video encode time is the same as my old computer. Does PowerDirector 17 support more than 4 cores?

Certain codecs only gain diminishing returns from additional cores. I think AVC and HEVC (h.264 and h.265) are among them.

Quote Certain codecs only gain diminishing returns from additional cores. I think AVC and HEVC (h.264 and h.265) are among them.

I've not really seen that with PD. The attached chart shows very good scalable performance for both H.264 and H.265 CPU encoding. Part of the scalable fall off is because most Intel CPU's have significant Turbo Boost capability, often 25+% or so. So for the lower proc usage, high clock multiples are achieved making the lower proc encodes faster than they really should be vs the higher proc encodes when the speed multiple reduces to nearly base clock.

For this comparison, 4k 60p 50mbps H.264 source was transcoded to 1920x1080/60p 40mbps for H.264 and 1920x1080/30p 11mbps for H.265. Two default profiles.

Similar behavior was also shown with PD17 here: https://forum.cyberlink.com/forum/posts/list/78633.page#post_box_322806

Jeff