Unlikely. TF2 ran fine on my integrated while my GPU died.
I'd pin it down to something being on a wrong setting, try fiddling around with things. Posting your system specs would help too.
I fixed that problem when I was on a Radeon 4350 ages ago, mess around with mat_queue_mode in console, mine is default to -1, but 1 or 2 or 0 might make stuff better or worse.
If it only happens in TF and L4D then it's some sort of engine problem within those games, not a graphics issue. Especially not with 270~ fps.