Before continuing on, here is a shot of the U-12 next to the U-9 for size comparison, as well as the Thermalright XP-90C.

For testing, I'm only going to use the supplied fans with all of the coolers.

With the exception of the XP-90C, all of the fans are setup in the "pulling" position (pulling air through the heatsink). I found this to work the best with these coolers.

XP-90C with 92mm 922 fan (push).
NH-U9 with 80mm 802 fan (pull).
NH-U9 with 92mm 922 fan (pull).
NH-U9 with 92mm 922 fan and 92mm 921 fan (dual, push/pull).
NH-U12 with 120mm 1201 fan (pull).
NH-U12 with 120mm 1202 fan (pull).
NH-U12 with 120mm 1201 and 120mm 1202 fan (dual, push/pull).

I used the 922 model 92mm fan instead of the 921 model 92mm fan for single 92mm fan configurations due to it having a higher CFM rating. All of the fans were run at full speed during testing.

Test System:

Dual-Core AMD Opteron 165
DFI Lanparty UT NF4 Ultra-D / SLI-modded
2x GeForce 7800GTX cards in SLI
2x 512Mb OCZ PC3500GX
2x 80Gb Western Digital SATA drives, raid0 striped
SilverStone Zeus 650W

To obtain load temperatures: Dual instances of prime95, one for each core, running the 'small FFT' torture-test for 30 minutes.
To obtain idle temperatures: 20 minutes of idling at the Windows desktop.



Conclusion:

The first thing that comes to mind is: Wow. I am impressed with the performance of these coolers. Up until this review, the XP-90C had been the best air cooler that I've had the opportunity to review.

Looking at the first four sets of temperature results from the chart above, the Noctua NH-U9 (while using the 29 CFM 80mm fan) matched the XP-90C's performance with the 37 CFM 92mm 922 model fan. I was very skeptical considering the moderate performance of the previously reviewed Tuniq Tower 112 (a cooler similar in design to these Noctua NH heatsinks) compared to the XP-90C. The smaller NH-U9 matched it's performance with the "weakest" fan provided. When using the same 37 CFM 92mm 922 model fan on the NH-U9 at 2700Mhz with 1.55v, the XP-90C falls behind.

The NH-U9 shows clear benefits from higher CFM fans as well as a dual-fan configuration.

The NH-U12 definitely benefits from the higher CFM 120mm fan (1202 model), but it loses a tiny bit of it's cooling capacity when adding a second 120mm fan. I double-checked this to verify my results and sure enough, they were the same.

All of the cooling configurations were surprisingly quiet, especially the NH-U12 with a single 120mm fan pulling through the fins. It would of course be very easy to turn this into an insanely loud cooler using a very high CFM fan, and I'm willing to bet the performance would only get better.

I wouldn't hesitate to recommend these coolers to anyone, however, I would check to see if the NH-U12 is compatible with your motherboard before buying one.

Pros:

Excellent cooling.
Easy installation.
Quality construction.

Cons:

NH-U12 is pretty large, may interfere with components on some motherboards.

We would like to award the Nocuta NH-U9 & NH-U12 the OCIA.net Seal of Approval.



Pricing:

As of writing, the NH-U12 sells for $59.95 with the NH-U9 going for $49.95 at a popular online retailer.

Thanks to Noctua for providing us with these review samples.