The Scythe Orochi is the largest heatsink ever to pass through the Frostytech Labs. It's big: 155mm tall, 120mm wide and a staggering 194mm long. The Orochi contains 10 heatpipes, weighs 1155 grams and from afar it looks like an industrial cooling unit of some sort. Scythe made the Orochi heatsink large for a reason, and paired it with a 140mm low RPM fan which is nearly inaudible.

When it comes to the number of heatsinks that can keep a 150W heat load in check while making less than 30 dBA, the list is pretty short. Fan noise from the 500RPM 11-bladed impeller is so low, you may have to double check that the fan's actually spinning. Frostytech's review of the Scythe Orochi is posted here, take a moment and give it a read.

In this article Frostytech is going to have some fun with the Orochi and conduct a little experiment with the help of one very powerful mil-spec aerospace fan. The Orochi heatsink comes with a 140x140x25mm fan that spins at a leisurely 500RPM and is almost totally silent.

This 500RPM fan is entirely sufficient for the heatsink, but we found ourselves wondering if the Orochi heatsink would perform significantly better with significantly more airflow?

Scythe Orochi Heatsink

heatsink specsheet manufacturer: scythe model no.: orochi scorc-1000 materials: aluminum fins, copper heatpipes, base, extruded aluminum base cap. fan mfg: scythe sy1425sl12l fan spec: 500rpm, 12v, 0.04a fan dim: 25x140x140mm heatsink & fan dim: 180x194x120mm weight: 1155 grams includes: multi-socket mounting hardware, thermal compound, instructions. Compatible with Sockets: 754/939/940/AM2, 478/LGA775 Est. Pricing: $62USD ($62CDN)

To find out, Frostytech mounted a mil-spec IMC Magnetics vane-axial fan on top of the Orochi heatsink. This IMC Magnetics fan has a working diameter of 120mm, and draws 24V, 5A to drive a cast-aluminum 12-bladed impeller at 6000RPM. Airflow is estimated at between 100-150CFM, but we haven't been able to track down exact specs. The model number is 04320-BD2510V and NSN is 4140-01-432-0292 (if you can track down a spec sheet let us know). A dedicated 24V DC Acopian power supply is used to power the IMC fan, which at full speed generates about 90 dBA noise.

Here's the business end of the 04320-BD2510V blower.

The Scythe Orochi typically stands 155mm tall, 180mm with the supplied 140mm diameter fan installed. With the IMC Magnetics fan sitting ont top, the total height is increased to nearly 300mm. That's clearly beyond the size of any regular PC case, but since Frostytech is doing this round of tests for fun I say bah! to feasibility.

Here's the IMC Magnetics and Scythe Orochi setup on the Frostytech Synthetic Mk.II test platform. The IMC Magnetics fan is 120mm in diameter, and 140mm tall - that should give a better idea of the scale of things.

So how did it perform, did a tornado of airflow significantly improve the Scythe Orochi heatsinks performance?