Currently I have the following mini-ITX system:

Athlon II X2 240 CPU
Zotac GeForce 8200-ITX mobo
4MB
Antec mini-skeleton case
28 watts on idle

I am thinking of upgrading the CPU and motherboard, possibly RAM as well. However, I would only do so if I can improve the standby power draw and reduce the fan noise even further. The current BIOS enables a very slow CPU fan speed so the system is already reasonably quiet. Also the CPU would have to be a major improvement on the current X2 240.

I also don't want to spend a huge amount of money, so a CPU in the mid-price range is what I am looking for. I prefer AMD for that reason, but can be tempted to Intel for good reasons. The motherboard only needs to have good fan speed controls and ability to undervolt and underclock.

Any suggestions would be greatly appreciated as I am really out of touch with current low watt CPU stats.

How do you use your CPU? What apps?

Mostly fairly lightweight apps (console based) and a Chromium browser under a very lightweight ArchLinux system. No gaming. Only CPU intensive stuff I do is compiling the odd C program and some image editing.

Intel's tech is simply much better than AMD's for general purpose computers nowadays, especially if you care about heat/noise. Intel makes you pay through the nose for their more powerful/capable chips but their low-end easily beats what you've got and has great value for your type of usage. Don't discount Intel's low-end.
Recent mainstream Intel CPUs are efficient and undervolt and underclock automatically. They idle quite low. Sure, you can do better manually but you'd be very far in the real of diminishing returns with your usage. So I think you should rethink your approach: forget undervolting and low-wattage. There are cheap CPUs which consume way less out of the box than their ludicrous power consumption ratings.

The biggest question you must ask is whether your usage would benefit from HT or a quad core (quads are of course much better). The price premium is significant but the cheapest Intel quads (don't overspend for marginal benefits) would be a huge upgrade over your current rig if you had a real use for multithreaded performance. If you want a quad, consider sniping a used Sandy Bridge.


I don't know what motherboard to recommend for its fan controls, sorry.
Cooling is easier than it used to be and the last motherboard I bought strictly on price (ASRock) had halfway decent fan control (good enough in my case).

Maybe it's just a "because I can" project, but you'd be better off saving the planet by switching off some lamps in the room or turning down the heating a bit.

What are you fans? Why is it too loud? Maybe you should switch to a closed case.

Does the Regor CPU meet your needs for computing power?

If so, the cheapest way to lower your power use would probably be to replace your PSU. What's in there now? If you really want to go quieter, consider a case with closed sides

If you want more CPU horsepower, wander through the Anandtech CPU bench and compare your CPU vs the i3-3220 (~$130) and others. AMD has the A8-5600K (~$110), A10-5700 (~$130), and A10-5800K ($130). Performance-wise, the dual core i3 wins over the Ax in just about all cases while using less power. At idle, they all look about the same.