360° View - Spire Gemini SP986B1-V2-2P Heatsink Information on Frostytech's test methodology is available here.
The twin 120mm fans rotate at 1600RPM and draw power from standard 4-pin PWM motherboard fan headers. Neoprene vibration absorbing pads rest between fan and fins to reduce vibrations. The nickel plated aluminum fins are split down the middle and closed off at both ends, effectively yielding two independent fin towers of approximately 61x62x103mm in size. The top and bottom surfaces of the aluminum fins are dimpled.
The Spire Gemini SP986B1-V2 heatsink stands 156mm tall, 125mm wide, and the bottom-most fin rests 40mm above the CPU socket for clearance. Fans are held firmly in place with springy wire clips. The six sintered-metal-wick heatpipes are positioned side to side at the base and intersect the 103mm tall fin stack in a sort of X-pattern. Each aluminum fin measures 0.4mm thick and is spaced 2.0mm apart from the next.
In the top view the dimpled aluminum fin surface texture and complete dark nickel plating of the Spire Gemini SP986B1-V2-2P heatsink are clearly visible. The 120mm PWM fans are arranged in a push-pull configuration. The hefty dark nickel plated copper baseplate measures 55x35mm in size. All six 6mm diameter copper heatpipes are soldered directly to the 4-6.5mm thick heatspreader, this ensures good heat conduction.

Base Finish and Flatness

Flipping a heatsink over to inspect the business end is often a simple indicator of overall cooler quality. More practically speaking, a heatsink is in many ways only as effective as the contact it makes with the processor - the flatter and smoother the better. Base finish is one of the criteria that Frostytech measure in the course of evaluating heatsinks, and it involves two distinct aspects. Surface Finish is the first; this is calculated with the aid of Surface Roughness Comparator that has a cross section of common machine surface finishes and their numerical surface roughness equivalents in microinches. The second is Surface Flatness. This is tested with an engineers straight edge or proven flat surface, in two axis.

The base of the Spire Gemini SP986B1-V2-2P heatsink is machined flat although there is a slightly ridged surface texture left from the tooling. Surface roughness is at or better than 32 microinches. The base plate is flat in one axis, slightly concave in the opposite.

Next up, acoustic noise measurements and then it's on to AMD/Intel synthetic thermal test results.