I wonder what is the Video Sequencer Rendering speed (fps).
Maybe I am doing something wrong? are there any recommended Memory Cache preferences? Should I use Disk Caching? Should I change the tile size in Cycles? Should I choose Fixed number of CPU cores? Or should I use Eevees? Or Workbench?
I have pretty beefy laptop Dell XPS 15, with nVidia 1650
64 GB RAM 2666 MHz DDR4
NVMe PCI 3x4 SSD, 2 TB Sabrent Rocket (advertised as 3500/3000 MB/s, I measured sequential Write/Read as 1400/1380 MB/s)
i7 9750H, 6 core 12 threads, 4.5 GHz
I undervolted the CPU to -115.2mV on CPU Core and CPU Cache -115.2mV, -24mV on GPU, AC CPU power set to 44 Watts on short and long load.
I ran Phoronix benchmarks on pts/cpu and it ran on all cores. all threads 100% for 3.5 hours, without a single throttle.
I ran the Phoronix cpu benchmark both on scaling-governor set to: powersave and performance, both had zero throttling, so I believe my undervolting is set to perfect values.
when I test render C4K 2200 frames (24 fps = 92 seconds of footage with no effects, just plain clip) on Blender,
it takes 14 minutes to complete 2200 frames of plain C4K clip export. that makes it 840 seconds to render 2200 frames, 2.6 fps rendering speed.
when I watch the top software while rendering, it uses only 260% out of available 1200% CPU power, which is effectively only using 16-21% of available CPU power.
RAM is not a bottleneck either, I have only few GB of RAM being used, < 5% in use.
NVMe SSD sequential write 1400 MB/s ( 1 frame of C4K resolution is only 8MB, so at 2.6 fps, we are writing only < 24 MB/s to SSD ). so I don’t think SSD is a bottleneck either.
and I experimented with Memory Cache from 0 to 1 GB, 2 GB and 4 GB. it makes no difference in rendering speeed. I also added Disk Caching, and it made no difference in rendering speed.
CPUs are not throttled, I am also looking at the temperatures monitor while rendering, and I get 80 C - 95C max (mostly 85 C), and watching System Monitor graphs of CPU threads in use, I can see CPUs are not throttled and not even at 25% of the available power.
I know it’s a lengthy explanation, but it might help others. I can’t find the bottleneck, as all my laptop resources are not fully utilised. Yet Blender can only do 2.6 fps in C4K export from the plain C4K clip, no transitions, no overlaying text, no effects.
My question is: what am I doing wrong? I can’t believe Blender can only run that slow.
Where is the bottleneck?
I installed DaVinci Resolve because I want to see how fast it can render C4K video. But DaVinci resolve menus and toolbars are so tiny on the 4K laptop screen, that it is unusable. I already posted on BlackMagic forum what I think about DaVinci not supporting 4K monitors in 2020. this is ridiculous to be frank.
Your kind advice on how to speed up Blender on my pretty beefy machine, will be greatly appreciated.