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. This Intel and AMD heatsink is so large, it should almost require slowly blinking red aircraft anti-collision lights... okay, that's an exaggeration. 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 full review of the Scythe Orochi will be up shortly, but in mean time I wanted to share this fun little experiment with you. The Orochi heatsink comes with a 140x140x25mm fan that spins at a leisurely 500RPM. This is entirely sufficient, but will the Orochi perform better with significantly more airflow?

To find out, we mounted a mil-spec IMC Magnetics vane-axial fan on top of the Orochi heatsink, rasing the total height to nearly 300mm. The 120mm IMC Magnetics fan draws 24V, 5A to drive a cast-aluminum 12-bladed impeller at 6000RPM. Airflow is estimated at 100-150CFM, noise levels hover around 90 dBA.

Here's the setup on the Frostytech Synthetic Mk.II test platform, what you can't see is the dedicated 24V DC Acopian power supply for the fan, sitting just outside the frame. The IMC Magnetics fan is 120mm diameter, and 140mm tall - that should give a better idea of scale.

So how did it perform?

It was ear-splitting loud for starters - 87.4dBA. Temperatures were excellent, but it also quickly became clear the Scythe Orochi heatsink is designed for substantially less airflow. In spite of the volume of air this mil-spec fan was dumping into the aluminum fins of the Orochi every minute, it didn't linearly improve temperatures to par with ambient. On the 150W Intel test, we saw a rise above ambient of 16.3 C, the 125W AMD test held firm at 14.5C over ambient. Both desirable results, and both evenly matched by the Xigmatek HDT-S1283 which runs 36.7 dBA quieter!

Don't worry, we'll pull the IMC Magnetics 6000RPM blower out for another heatsink test in the future... In the mean time, check out Frostytech's full review of the Scythe Orochi heatsink.