The Heatsink Fan:
The 100x100x25mm fan is mounted to the base of the Scythe Katana II SCKTN-2000 heatsink such that it floats just in front of the 51 slanted aluminum cooling fins. The fan spins at 1500RPM, generating less than 38dBA noise in our measurements. It connects via a standard 3-pin fan header to the motherboard and supports RPM monitoring. Each aluminum fin is approximately 53 x 105mm in size.

Heatsink Top:
The Scythe Katana II heatsink stands 144mm high and the finned portion makes up about 110mm of that. The aluminum fins are elevated a good 30mm above the base to provide clearance for capacitors or MOSFET heatsinks near by. In the image to the left you can see how the slant of the aluminum fins will cause airflow to directly impact the metal as it passes through. Each fin measures 0.3 mm thick and is spaced approximately 1.75 mm apart.

Heatsink Side A:
The 100mm fan is positioned in front of the aluminum cooling fins, but affixed to the base of the heatsink. There is no fan grill to protect the heatsink fan from errant wires, so keep the inside of your case neat and tidy!

Heatsink Side B:
Looking at the rear of the Scythe Katana II heatsink we see approximately 95x105mm worth of cooling fin ready for business. The three copper heatpipes are soldered to the copper base, and a simple interference fit holds the aluminum fins tightly around them. At the base is a steel plate for the different mounting clips to attach to.

Heatsink Side C:
From the side, the slant of the aluminum cooling fins is more evident. The three heatpipes are soldered to the copper base plate which is about 4mm thick. A thin highly conductive base is ideal for rapidly conducting heat energy away from the CPU and to the heatpipes. The slant of the aluminum fins interfacing with the cylindrical copper heat pipes creates an oval hole. This is the OFCS aspect Scythe talk about on the side of the box... the true impact is apt to be minimal. Front to back the heatsink is about 76 mm thick. Notice how the fan is held with a metal support bracket that attaches to the bottom of the heatsink. The top of the fan comes in contact with the aluminum fins, which may lead to rattling or other noises later on.

Heatsink Base:
The copper base of the Scythe Katana II heatsink measures 34x38mm in area, just a little undersized for Athlon64 processors. The metal has a smooth polished finish, with surface roughness at or better than ~8 microinches (excellent). The base is perfectly flat in both axis. The CPU mounting brackets attach to the steel flange on either side of the copper base with four screws.