[Solved] Phenom II 940 roaring like a monster

So, I just finished my first system build, and everything seems to have worked out okay, with one exception - my AMD Phenom II 940 (with stock fan/cooler) is incredibly loud, in an obnoxious whirring sort of fashion. I've looked this up and apparently this is abnormal.

As I was writing this post, the fan/cooler started whirring extremely high (after the computer running for about five minutes) and sounded as if it was going to explode. I quickly reached for the power switch and shut it off, so I don't think any damage has been done (though we'll see!). Any ideas what could be causing all this?

If the fan is making a horrible high-pitched squealing noise (I've had a fan make that noise, and it is horrible and headache-inducing), then, like, replace the fan. While you're at it, replace the entire cooler - I'm sure the stock cooler is just about the least-optimal choice you can make. Look into something by Scythe.

Yeah, it's likely I didn't seat it properly. The thermal paste was pre-applied, and no extra was included - meaning I can't really remove it as I have nothing to re-apply. So I suppose I will buy an aftermarket cooler (will look into the ones you recommended). Thanks for the advice! Do most of them come with thermal paste, or do I have to buy that separately?

Understood. One of the coolers chunkymonster recommended, the Sunbeam Core Contact Freezer, comes with TX-2 paste, runs very quiet, and has a $10 rebate at Newegg, so I think I'm gonna go for that. There are probably more powerful coolers on the market, but I'm running a pretty cool machine already (no overclocking, one graphics card, super-ventilated case), so this should suit my purposes fine.

Thanks so much for everyone's help!

Check your temps. I had such an issue with a build awhile back and for some reason the bios was reading a different temp than any software I used to check it. The bios had a fan setting for automatic fan control and I adjusted the temp for when it kicked in full blast.

I use a Noctua NH-U12P cooler for my PII 940 (temps are below 55c under load). It's a little expensive, but I can't hear it over my video card. (also it comes with good paste, better than AS5)

Actually AMD has had a better stock fan for quite some time. The heatpipe cooler they used starting with the dual core opterons are as good as some of the inexpensive aftermarket coolers. Intel heatsinks are horrible. My Intel rig used an aftermarket one right from the start.

My last AMD board was a socket 939, so maybe some things have changed - but based on pictures, I don't think they have. Getting the heatsink onto the CPU is easy, and there's no worries about it coming loose. The problem is that getting the heatsink off again is nearly impossible! Last time I tried I wound up yanking the entire CPU out of the socket (no damage, fortunately), because the thermal paste has the two gummed together, and the plastic border prevents you from twisting the heatsink to separate the two.

When I went to a 775 board with my current setup I went out of my way to get something with a backplate - more of a pain to install for sure, but if the time ever comes I am sure I will have little trouble removing it.

The heatpipe cooler has changed little since the S939 dual core opteron days really. The standard aluminum ones I agree are not that great but the new ones seem better than the old ones. You would think they would put better heatsinks with the triple and dual core PH II BE's though. Only the quad gets the heatpipe one. I took mine and put it on an old S939 X2 I had lying around that i keep meaning on putting back together and giving to a family member.