My old laptop would run at 75 celsius when it was heavily strained.
I left something running and went to sleep not realizing it was still open, and when I woke up half the motherboard was part of the table.
90 celsius is srsly not very safe bro. They can run at that sort of temperature but they really shouldn't - my new computer is sort of upper-middle-class in an Antec 900 with no extra cooling features, just the basic case fans, and I'm yet to even get the system above room temperature. Then again I don't really play many high-spec games, since almost every game that's hard on your system now is an FPS game and I stopped enjoying them around the release of Deus Ex 2.