Installation:
I'm always enthused to see different manufacturer's approaches to multi-platform mounts on CPU coolers. We've seen some here that work really well, some that provide a fight to install, and others that downright will not work on one platform or another's motherboard style. To install the XiR-3500 you must first loosen the four screws on the bottom side of the cooler. These will loosen the bottom base of the cooler allowing you to slide onto either side the bracket for which platform it will be installed on. For our testing here, we will be installing it on a socket 939 AMD Athlon 64 system.

When I took the protection sticker off the copper base of the heatsink, I was impressed to see how smooth it was lapped down to. There wasn't a single imperfection or bump on it, just purely smooth copper to make great contact with the CPU.

I found the AMD brackets to have an interesting approach to latching themselves around the AMD cooler retention bracket. Being used to the typical clip-on style or the style that bolts right into the back plate, this screw-to-tighten approach only caused me minor fuss when installing. I found that the brackets, even when pushed all the way in at the base, seemed to protrude just a bit too much out either side. Getting each end to line up and not overhang the plastic retention piece on the motherboard was tricky. It took a lot of playing with and failed attempts before I finally got it to line up where each bracket could just grab enough plastic to hold on.

Testing:
To test the XiR-3500 I used our usual CPU test; CPU temperatures were recorded under both idle and full load conditions. The results are shown below along with a discussion.

Testing System:
CPU: AMD Athlon 64 3200+ (Socket 939) @ stock speeds
Motherboard: Biostar NF4UL-A9
Memory: 1gb (4x256mb) PC3200 400mhz
HDD: Western Digital 160gb SATA II (WD1600JS), Seagate 250gb SATA II
Video: Asus EN7600GS Silent
Sound: Mackie Onyx Satellite Firewire Audio Interface
Power Supply: Seasonic S12II 500W
OS: Microsoft Windows XP Professional SP2
Additional fans: (1) 120mm 800RPM intake, (1) 120mm exhaust, (1) 120mm low-RPM power supply fan

Test Results:

Idle: 40
Load: 46

Although the Nexus cooler was a bit higher with it's idle temperature than my past Spire VertiCool IV, it's lower load temperature was certainly a perfect balancing point. I don't mind two degrees warmer during idle if it means a near 7 degrees cooler when under full load BUT at a fraction of the noise! I was certainly impressed with how quiet this cooler remained, even when the fan was running at the full 2500RPM. Going all out, I could only hear it a small amount over my 120mm Nexus exhaust fan which isn't a bad price to pay considering most CPU coolers are dramatically louder than this one was.