Okay, I just tried Half life 2 update at 4k via vsr and it runs in the high 200's to mid 300's so there's no limit that I can see.
They have got a 95 fps limit you can put on it manually which is plain dumb, we've spoken about this before. It's a stupid limit for those with 120/144 hz screens. I don't mind it at the moment because my screens got a 75hz limit but yeah if I had a higher level screen I wouldn't be happy, I imagine it will be changed unless there is something causing the limit, Another annoyance is it only works with DX10 and 11 titles when DX9 titles are the ones more likely to hit crazy high's and actually need such a feature. But as I've said elsewhere today AMD haven't been making smart choices lately. Hopefully someone will pull there finger out soon so they can start fixing all these silly little oddities.