This might not be a problem at all. I recently put together an AMD A4-3400 and an aftermarket fan. When I ran burn in test I was running at approx 22C under full load (granted for only 5-10 minutes). But without knowing your specs its hard to say. Internal temperature could be many factors, type of CPU, power draw, CPU Fan, ambient space, case fans. If your PC is running slower than you are used to I wouldn't put to much worry. Try running a burn in test using Prime95 for 30 minutes and post your specs, this way we can see if there's an actual problem.