After replacing the old thermal paste that I had on my CPU with Arctic Silver 5 thermal compound, my CPU fan began to spin at a higher rpm than usual. It has gotten really loud and it really bugs me. Normally my CPU temps are around 30-35 degrees Celsius but they've recently increased by 10 degrees (now hanging around the high 40s). I'm not too sure why and I'm a bit worried. My CPU is an Intel Core i5 3450 processor and I have an MSI Z77A-G41 motherboard. Any help would be appreciated. Thanks.
Here's a screenshot of my CPU Hardware Monitor.
Arctic silver 5 has a set in time. they say it's about 8 hours of operation for 2 weeks before the thermal compound would reach its peak/rated cooling.
Idle temps are not that important. Monitor load temps. if you start to see temps in excess of 90C, you may not have all the legs of the heat sink pushed in properly or one of the legs may be damaged and this may result in a lose heat sink.
The other possibility would be that you may have put too much compound on the heat sink. A pea sized amount is good enough (actually more than enough).
If you load temps are hovering under 80C, there's a good chance they will improve after about 100 hrs of working. For Intel cpus the rule of thumb could be that for gaming and general load testing you should be below 75C.