This is more of an FYI, but I'd certainly be interested in other's thoughts or observations.
One of my workflows for working with VHS tapes is to capture and then deinterlace them into MagicYUV AVIs at 50fps, then bring them into MMS for editing, cropping and applying various effects including Neat Video.
I then export them as 1440x1080, 50fps MPEG 4s ie H264 at 5000kbps.
With the RTX 3060, I'm achieving an export speed of around 30% of real speed ie it's taking me 3 times as long as the movie to export. This is, to put it mildly, incredibly frustrating given I get around 1200% when exporting from MP4 source files. The 3060 is working at around 30% with the CPU around 15%.
After a 12 hour+ export overnight for a ~4 hour tape, in desperation I put all 3 HW acceleration droplists to the UHD770 and lo and behold, I achieved 100% exporting speed. The 3060 stayed around 30% (but jumped up and down a lot) but the 770 was steadily running at around 35%, with the CPU now at 35%.
My takeaway? For export, if you're not happy with your export speed, experiment with the HW acceleration settings, as it appears the export speed depends on the source.