Noctua NH-U9DO A3 AMD Opteron, 4 Dual Heat-pipe SSO Bearing Quiet CPU Cooler

Pros: The size of this heatsink/fan makes it ideal for a 4U server. I'm using this on an Opteron 4386 in a ASUS KCMA-D8 motherboard and it is the right size for it. It is also really quiet, especially compared to the louder case fans that came with my server case.

Very simple to install as well. Comes with everything you need, such as wrench and thermal paste.

Cons: When using the L-shaped hex wrench vertically, the handle is really small and uncomfortable to turn. I ended up holding the wrench with some vice grips and this made it a lot easier.

Other Thoughts: I read some of the bad reviews about getting the screws in for the brackets and can possibly see where that might be difficult to get started if you have larger fingers. I'd say I have average to slender fingers and had no problems with the 4 screws that attach the brackets to the heatsink.

On an 8 core Opteron 4386, I'm averaging about 104 degrees F with light loads (running 5 virtual machines).

Pros: Looks sturdy

Cons: I spent more than an hour to insert the screws to the base. They don't fit. The screw driver in the box does not fit the head of screws, either. I have been building computers over 10 years. This is the worst cooler ever purchased to assemble.

Other Thoughts: When you spend $80 for this cooler, it should not be so difficult to insert a screw to the base.

Pros: Looks like an awesome cooling design. I would do 5 eggs if the bracket screws were not an issue.

Cons: Plan on spending about an hour trying to get the tiny bracket screws on. This is not acceptible!!!!

Pros: Keeps the CPU cool...

Cons: One of the bracket screw holes did not align with the cooler mount. I had to enlarge the bracket hole with a 9/64 drill bit so the screw would go in straight without stripping. This is just poor workmanship on the manufacturer's part!

I should not have to physically alter this cooler...

Will not buy another.

Pros: It's very quiet, and it keeps my AMD Opteron 6348 nice and cool. So cool, that I'd overclock if the CPU/motherboard would allow.

Cons: A minus, but not enough to take off an egg, is that screwing the clamps to the base can take some patience, as there isn't a whole lot of room to work with, and the angle is a little awkward. Still, that's not a major issue.

Other Thoughts: As with all coolers of this type, you must be careful to have enough room to work with, especially with regard to memory modules. If your DIMM slots are close to the CPU (which they usually are), then some types of memory will be too tall to coexist with this cooler. It's advisable to look for "low profile" memory if you plan to use memory modules in DIMM slots close to the CPU. I used G.Skill 'Ares' series modules, which fit, with about 2mm to spare.

Pros: Easy to install. Solid design, works as designed.

Cons: None!

Other Thoughts: I was dreading installing the heat sinks for Asus KGPE-D16 dual socket G34 AMD 6274 CPUs (having installed others few years back that were a pain). But fear not, this heat sink is easy to install and is well-designed/engineered. Make sure to read the well written install guide. Why can't all products be designed like this? Fans even have arrows on the side to show you which way the fan turns/air flows.

Pros: Works amazingly well. With my 6274s, my idle temps with no load at all are 12C, and with 5-10% load, 17-20C at nearly idle. Does an AMAZING job of cooling the CPUs. Was blown away by how cool it was running when I first saw it on iKVM.

It also feels surprisingly lightweight in it's design. Felt VERY comfortably attached, and didn't feel as though the weight was stressing the board or flexing it too much at all.

Cons: Speed isn't variable via the motherboard itself. Just really has one setting as far as I know, which is just 'on'. You can hook up adapters though to lower the speeds, but I don't really see the point.

Other Thoughts: The included L wrench is a bit... difficult at times to work with. Especially when you're trying to attach the heatsink to the motherboard, it can be a little bit of a pain -- but otherwise makes this design 'all tools included'.

Also be aware you might need to shift the fans up a tiny to leave some space for memory, depending on how high up yours goes and the board design and the orientation you choose for the Noctua. On my KGPE-D16 I had to just move it up a notch or two to clear the memory with good space when I oriented the fans to blow the air upwards. Works GREAT though despite a slight shift up.

Pros: The best cooler I have ever used. Was used on an AMD Opteron 6272 and was able to keep it cool in the 20 degrees range. Excellent cooler.

Cons: The thermal paste it came with felt cheap. Use some Arctic Silver 5 instead.

Other Thoughts: This was used for a very expensive workstation computer. The computer was made for 3-D design & modeling, professional video editing, and much more.
The full specs of the computer are as follows:

1 x SilverStone RAVEN Series RV03B-W
1 x ASUS KGPE-D16 SSI EEB 3.61 Server Motherboard
1 x Crucial M4 CT128M4SSD2 2.5" 128GB
1 x PNY VCQ5000-PB Quadro 5000 2.5GB 320-bit GDDR5 PCI Express 2.0 x16 HDCP Ready Workstation Video Card
2 x Kingston 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) ECC Unbuffered Server Memory Model KVR1333D3E9SK2/8G
1 x AMD Opteron 6272 Interlagos 2.1GHz Socket G34 115W 16-Core Server Processor OS6272WKTGGGUWOF
1 x SeaSonic X750 Gold 750W ATX12V V2.3/EPS
1 x SAMSUNG EcoGreen F4 ST2000DL004 2TB
1 x Noctua NH-U9DO A3 AMD Opteron CPU Cooler
1 x LITE-ON Black 12X Blu-ray Burner with Blu Ray 3D Feature SATA IHBS112-04
1 x Rosewill RCA-1204BL 120mm Sleeve 4 Blue LED Case Fan, 4/PK

Pros: After running my CPU (AMD 6272 Interlagos) at 100% for hours, the temp never exceeded 35 C. The CPU generally sat at around 28C-30C. Absolutely incredible performance.

Cons: The fans are somewhat bulky. For my motherboard layout, I was unable to use my video card because these monsters hung over my 2.0x16 slot.

Pros: Effective and quiet cooling. Using this cooler on the Interlagoes 6220 with no problems. At first I thought the cooler was a little undersized for wattage of this chip but it has no problem keeping up under BIG compile jobs. I have reconsidered the size and realized that the smaller form factor allows you to use this cooler on dual processor boards without issue. I can access all the memory slots on my ASUS KGPE-D16 with the cooler installed and there would be no problem installing another one of these coolers when adding another proc.

Cons: Dual fan can present an issue and did for me: I don't have enough pin outs for both fans with a case fan plugged in to a pinout. Of course I can move the case fan to a molex but it's nice to be able to control the fan from the BIOS. This has more to do with motherboard layout than anything but consider it if you are using a tower case.

Other Thoughts: Really quiet; no problem sleeping in the room where this system (installed in a HAF 932) is running.