Ok, so here we are
I've recorded a lap from a replay of a recent league race in Assetto Corsa.
Steam and the game are running from an SSD and recordings are made to a separate SSD.
I haven't included Lagarith recordings from either Afterburner or Dxtory because they resulted in file sizes around the 8GB mark for the just under 2 minute vids.
I didn't feel that quality was notably better than the best of the others anyway tbh - certainly not enough to justify the file size.
I also didn't include Fraps, as you can only record 29secs unless you buy it. That 29sec vid was still a 2.4GB file and as above, not worth it IMO.
There aren't many settings in there, so if setting it to 1080p @60fps isn't doing it right, oh well.
OBS isn't here because I couldn't be bothered to trawl around looking for good settings/codecs etc, or go through a lengthy trial and error session.
Afterburner NVENC default settings LINK 90MB
Given the very small filesize, it's not surprising that this is the worst of the lot.
It might be good for other types of games though. Perhaps something that remains fairly static vs lots of panning shots.
DXtory VFW x264 LINK 602MB
Mirillis NVENC LINK 429MB
^^These two had the biggest performance hit, or at least the lowest minimums.
In the case of Mirillis, I'm not sure if that had anything to do with locking fps to whatever recording rate you've set it to.
Afterburner NVENC MAX settings LINK 718MB
Afterburner VFW x264 AVI LINK 554MB
Afterburner VFW x264 MKV LINK 637MB
Same settings as above and performance hit is the same
Shadowplay MAX settings LINK 697MB
The above are all much of a muchness, though you may have better luck finding any obvious differences between them.
I take back what I said about Shadowplay though. It's on par.
I haven't covered every base here. There are alternate recording codecs in Mirillis (avi/mp4) and many options to play with in most of the other software.
What would I choose? Probably Afterburner VFW/x264.
ED: Don't go by the web player. Download the clips to see the actual quality.