Speed issue in Win 11

Help/How To
1

Context: I just upgraded my machine and now I see wildly bad render times in windows 11.

All the same video project for the tests, all encoded with the same h264 profile.

Original Machine: i5-6600k, nvidia 1660 super, Win10 - encoding time 15mins
New Machine: AMD 9900x, nvidia 1660 super, Win11 - encoding time 20 mins
New Machine: AMD 9900X, nvidia 1660 super, linux mint - encoding time 5 mins

What the heck is going on with windows 11/shotcut that actually slows down the encoding times?
I’m just taken aback because the new processor benchmarks at 9x faster than the old one. I tested with CPU encoding and GPU encoding and in all cases windows 11 on the same hardware as linux mint takes 4x longer, and longer than my 9 yr old setup on win10.
Anyone know a fix for this?

2

What version of Shotcut are you using for all the tests?
Also, what are your export settings?

3

I’ve got version 25.01.25

movflags=+faststart
preset=fast
f=mp4
acodec=aac
channels=2
channel_layout=auto
ar=48000
ab=192k
vbr=off
vcodec=h264_nvenc
vb=10M
g=120
bf=3
progressive=1
top_field_first=2
deinterlacer=bwdif
rescale=hyper
frame_rate_num=60
frame_rate_den=1
threads=3

4

One explanation is if Export > Video > Parallel processing turned on in one setup but not another.

5

Parallel processing is turned off in all 3 scenarios. Consider I’m using the GPU codec h264_nvenc. However the results are similar ratios when using a CPU targeted codec. Win 11 just seems unusually slow. I may end up reinstalling win 10 on the new hardware and testing that again as well or just drop windows entirely and stick with Linux.

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