[FFmpeg-user] Windows 10, ffmpeg concat/demux is slow... part 2

Kevin Duffey kevinmduffey at yahoo.com
Mon Nov 13 17:56:30 EET 2017

> As one of the drives 
> is an SSD.. this seems ridiculous to me that it is basically moving at 
> USB2 speeds. At the very least, as it is over a USB 3.1 gen 2, 10Gb/s 
> wire... it should be much much faster than this. So now I am left 
> wondering why my system is super slow at copying files. Is there some 
> configuration in Windows 10 that has to be enabled to allow fast 
> copying?

I don't know. In the case of the external disk above it seems a hardware 
limitation. Either the disk or the USB3 interface of the disk or the 

ok.. see if the quote thing worked lol.
So just to be clear, I have been building computers, networks, etc for many years now.. only saying that to ensure that for the most part, I understand the various speeds that USB, SATA, etc should be able to do. Not that anyone was totally questioning that of me, but wanted to throw out there that I do have the knowledge of the basic hardware stuff.  It is in particular with ffmpeg that I am blundering.
With that in mind, lets assume I had nothing but SSD drives. My laptop has 2 NVMe 960 EVO drives, and one SATA3 SSD. For clarity, it is a SAGER desktop replacement laptop.. not very portable. Also has a 2TB Firecuda SSHD and 64GB RAM with 6700K cpu.
What sort of speeds should I see when concatting two DNxHR SQ 4K videos together?  That would help me understand better what to expect. I would assume from some other posts I found around the interwebs, that I should see 150fps to 300fps  with this process, not what i see now at a paltry 9fps.  If this is a CPU bound task.. the CPU indicates it is using 1% total.. but the disk usage shows at about 20%. So I would assume that I am still not being hampered by disk i/o given that it is not maxed out.
I will be building my threadripper system in a couple weeks.. I hope that ffmpeg will benefit from the 16 cores and be much faster... assuming I can get past whatever the issue is with why it is so slow now.


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