My new PC is pretty loud. How do I tell exactly what is making all the noise? I think a lot of it may be the processor fan, so I've been looking to replace that. My temps seem to hang around 45 degrees for the CPU. Is that good? That's with a heatsink/fan combo that came with the unit.

If I were to get a better unit that would be quieter and cool better, what would you suggest for an AMD 2100+?

I dunno what is "current" now for HSF combos - its been several months since I've shopped that. I would check out hardocp.com, they had an excellent HSF buyers guide a few months ago - I'm sure its still around. They rate cooling abilities, loudness, etc - basically all the points you're asking about.

Tom's Hardware very recently did a rundown on 55 heatsinks and fans for the Athlon.The article is here.

Hmm, that article says this:
"The internal temperature, TA, immediately surrounding the cooler must not exceed 40° Celsius, no matter what the operating state of the CPU is."

If my mobo temp monitor says the temp in the CPU is 45, is that bad?

From that description it sounds, to me, as if it's the ambient air inside the case just by the cooler that mustn't be warmer than 40 degrees. That's the way I parse it anyway...

/Michael

45 degrees is fine, especially if you're not overclocking. I have a 1.33 (non-XP) T-Bird which is about the second hottest CPU ever produced - it runs reliably up to about 55 degrees with mild overclocking.

However, stock HSF combos tend to be either loud or useless. You might want to check out if any of the 80mm copper-based monsters will fit on your motherboard. These will allow you to run an 80mm fan at a slower (=quieter) speed and obtain the same or better temps.

After the CPU, check out PSU / case cooling. Some PSUs have rather loud fans that can be replaced with quieter versions (warning - high voltages can be present within PSUs even when disconnected - if you're not comfortably proficient, consider looking around for a quieter PSU). Case cooling can also be done with quiet fans. You can often get better cooling from 2 nearly silent slow case fans as you can from one loud fan.

There's been at least one lengthy discussion on this, just in case you hadn't searched yet.

I use Panaflo fans in my case, 2 in the back, and one in the power supply, with a variable speed YS-Tech fan on the heatsink. I have a Thermalright AX-7 heatsink. Alltogether this cost under $100 online. I can only hear the computer if I'm sitting at it, from 10 feet or so away you can't tell it's on.

It's likely your HSF is the culprit, they usually are because of the extra work that they need to do. I recommend getting the best heatsink you can, and then a quiet fan to put on it. Same results as an OE heatsink with a super-mega-loud fan.

Well, the standard method for determining what's causing what's happening (no matter what ``what'' is) is to test each possibility one-by-one. In this case, I'd say that, since you can't disconnect all the fans (the power supply one will always be on), you could disconnect each fan one-by-one. But the CPU will heat up very fast, so power it off and let it cool down, disconnect the fan and power it back up. Listen for a few seconds and turn it back off. You shouldn't even make it past the BIOS.

55? Bah! Try Dan's Data Cooler Comparison. Not only does it list a huge number (over 110 Athlon coolers alone) but he's got the degrees per watt rating of each cooler, which makes it very easy to work out whether something's going to dissipate the wattage your CPU generates. He's also got reviews of water cooling and other bizarre equipment, and his testing process is very good. I recommend it.

Have fun,

Paul