Not too long ago I figured out that there was a very minor difference between using V-Sync and not using it. With V-Sync enabled, you won't be able to jump to the maximum height when you do a buffered full jump after a short hop or land with a low downward vertical speed. This is true for both versions... I remember Noclip having this problem and thought it was just bad play, but it seems to be a huge problem for people who want to cut corners to optimize their times. If you still are unsure how this works just ask and I'll try to explain it differently. Any opinions on this are appreciated.

Yes, this means that my 4:45 non-steam apparently didn't use V-Sync, even though we encourage everyone to use it.

TL;DR: V-Sync occasionally causes problems with buffered full jumps.