For CPU, it should be under 60. For GPU it should be under 70 or 75 atleast.
Mine reaches a maximum of 90 degree celcius,is that normal?
Normal?? That's totally ABNORMAL. You'll ruin ouir card with that temps. If you've overclocked your card, reset it to default. Overclocking increases card's load and temp. make sure you've proper cooling. Don't game with that temp (90C) ever.