video card overheating or what?

[oneshot]

so It seems like when I have my computer on for maybe more than an hour when Im browsing through my album artwork in itunes it becomes laggy.

Not really a huge deal but I was wondering if this was because of my computer overheating because thats what it seems like?

Also a side question is that safari also seems to crash quite allot. Lots of times it seems like when opening a web page that is taking a while to open.

-Thank You