Sounds spot on. When was the last time you cleaned your fan? You should make a habit of doing a clean out once every 6 months at the least just to keep it ticking along nicely at good temps. More if it's in a particularly dusty environment or if you keep your machine on a carpeted floor. I keep my machine on the floor, which is carpet, but it's on a bit of wood too so it's not sucking dust up from the carpet into the PSU fan.