I have OC'ed a friends i5 2500k to 4.2ghz and running BF3 the temps seem to hover right around 70 which seems a bit high sense the cpu never seems to be running over 75% load. Just curious if this temp seems ok or there could be an airflow problem considering under 100% load the temps could be significantly higher?
I purchased a cheapie Xigmatek GAIA SD1283 heatsink+120mm fan combo and I have to leave the lid off cause its too wide, but it's worth it. With the locked i5 2500 I have it OC'd to 4.1GHz on all stock settings except the multiplier at 41x, and passed intels test utility @65-72C max which stresses even more than Prime95 by around 10C. (unfortunately I made a mistake in my purchase not buying the 2500k, but 4.1GHz is enough)
According to speedfan the core temp doesn't go any higher than 54C @ 1920x1200 set to ultra in BF3. So... use thermal paste generously
I forgot to mention to scrape the ooze off the sides of the CPU. haha. The one I used is a screw-on mount and not just a bracket so it oozes out the excess with a tight fit. Toothpicks are amazing at picking up the paste without spreading it.
You can cover the whole cpu without excess or having to go back and cleanup after yourself. Of course you want to have the best coverage but generous amounts of paste is not the way to do it. This is why there are so many different methods for applying paste with different types of coolers.