What model i5, is it overclocked? 180F=82C which is quite high (especially if during gaming). Steps I would take here.
1) Blow all dust out of computer making sure to clean all fan areas good and the heatsink itself. If cleaning doesn't fix it
2) Reseat heatsink and apply fresh thermal compound. If reseating HSF doesn't fix it,
3) lower clocks - or even take CPU back to stock speed
Hope it helps