This is the number that you want to beat.
Thermal Resistance: 0.17°C/Watt
Anything higher is a waste of your money.
If this number is not given, move along.
Oh by the way this is from the Arctic Cooling Freezer 7 Pro, $32 retail.
Everyone yells Zalman Zalman Zalman, well guess what I don't find any Thermal Resistance information on thier
web site or in the coolerss manuals. They are over priced anyways.
XIGMATEK HDT-S1283 120mm Rifle CPU Cooler
Thermal Resistance 0.16°C/Watt
$44 shipped
$10 for .01 Degrees C/W at best a cooling of 2 Degrees C, to me it's not worth the hassle of install and expense.
Scythe SCINF-1000 120mm CPU Cooler Thermal Resistance unknown price higher than prior units of know capability.
Tuniq Tower 120 P4 & K8 CPU Cooler
Thermal Resistance 0.16 - 0.21 °C / W from web site, $57.58 delivered.
Again over priced and a pain in the ass installation.
Bang for buck winner here, the Arctic Cooling Freezer 7 Pro.
Why bother with anything else?
A post script to the above:
XIGMATEK has a new unit out the Xigmatek Achilles S1284 for $45 before shipping.
Thermal Resistance 0.14°C/Watt
This may be the new big boy on the block.
$52 shipped from;
http://www.newegg.com/Product/Product.aspx?Item=N82E16835233017&Tpk=S1284
With installation of the XIGMATEK' being so problematic and almost requiring the extra mounting bracket,
that costs an extra $10. I would still go for the Freezer 7 Pro.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835186134