IF YOU WANT A SILENT AND FAST PC, but don't want to go for watercooling, the only way is to increase the size of those darn CPU fans. Here's one that stretches it to the very limit: Thermaltake BigTyp14Pro.

Despite the size, this biggie is still decent looking without too much bulk, as there is a plenty of empty space between the heat sink fins and the CPU actually.

We put it on our reference Intel Core i7 test rig, the 965 Extreme with Asus P6T Deluxe mobo, all fed by 3GB of Kingston DDR3-2000 optimised RAM. The check was the temperature in BIOS at both the standard 3.2 GHz frequency at 1.1 volts, as well as overclocked 4 GHz setting at 1.4 volts. Both Turbo and HT were off.

Here's the BIOS monitor 3.2 GHz screenshot

And heres's a 4 GHz one, with chasis fans off too for a worst case situation ... both taken after around five minutes of operation to stabilise the temperature.
Hmm not bad! Note that the mobo, at 42ºC or so, is still kept tolerably warm rather than boiling hot despite the immense heat coming out of the X58 chipset here. But, more than keeping the performance, the important thing was the utter silence. As the system booted out of SSD and there were no other high-speed fans in there, no high-RPM shriek disturbed us.
In summary, a good heat sink with Core i7 support too, good airflow at minimum noise, and yeah, it can still keep the surrounding mobo area OK even without extra fans. µ
The Good
Well performing at very low noise, no push-pin crappy mounting, not too ugly either.
The Bad
Check your casing and mobo chipset heat sink clearance before mounting this monster
The Better
Big fans are less noisy - and yeah, size does matter
Bartender's Verdict
What no stats with the cpu running at full load? Also with the cpu at idle the fan should be silent, duh.
I installed a large copper heatsink in my rig, a thing of beauty it was too.
My PC would crash every so often, swapped out just about everything.
Then I place the motherboard horizontally - no more problem!
I think the weight (and height) of the cooler was distorting the mobo, replaced it with the cheaper alumunium/copper version and the problem was gone for good.
eBay'd the all-copper one.
Happens a fair bit with Thermaltake Coolers, its their terrible mounting system combined with a shift of weight from the bottom to bottom/fairly even to a very topheavy cooler.
Mounted in a tower case if any of the nuts holding the cooler on loosen a bit you will start to make less contact with the CPU and eventually the thing will turn itself to prevent overheating.
This has happened to me with both a Tt SilentTower and a BigTyphoon.