I have a system with integrated graphics to which OS X has assigned 1.5gb (out of 16gb) of RAM, however iStat Menus is currently reporting this at around 95% full, even though I'm not currently running anything that should be making much of a demand of the GPU.
Of course it's possible there's something I'm not aware of that has been using the GPU, but only restarting has completely cleared it. I was playing Civilisation V yesterday, but even while playing it didn't fill my video memory, and that was over 10 hours ago (my computer hasn't been asleep since then, as I'm still running through a large initial backup of a huge volume).
I'm just wondering if there's an easy way to determine what's using up all this video memory, similar to using Activity Monitor to track main memory? If it happens again I'd like to figure out what's at fault so I can avoid the problem in future and/or report any memory leaks or similar issues.