>>1050064 (OP)
I have the same problem as well. Whenever someone posts a .webm larger than 600 Kb or so, I have to download it with a download manager and use an offline video player to be able to watch it properly. I doubt the tech support pajeets >>1050076 will be any help anyways.
Funnily enough, one thing I have noticed is that often I have a much easier time watching webms I've encoded and uploaded myself (even when they're relatively large), even on another computer using a different isp. So either because they're being cached on a server closer to where I live, or I wonder if it might have something to do with the way they're being encoded.