SilentFlux ATX ™

Heatsink Test – Joe

SUMMARY: Low noise, light weight thermosyphon heatsink with OK performance.


The good guys at Directron were nice enough to send a sample of the SilentFlux ATX ™ to test out. This is a thermosyphon type heatsink using R134a for the fluid medium.


Key Features

  • Thermosyphon heatsink
  • Size: 80x132x135; Weight: 400 grams; Material: Aluminum
  • Fan: 92mm, 2100 rpm, 37 cfm, 29 dBA
  • Uses R134a refrigerant
  • Mounts for AMD 754, 939, 940 and AM2, Intel LGA775 and P4 and Pentium D

A view from the back shows the condenser and boiler, with two tubes for coolant flow:


Parts that ship with the SilentFLux include mounts for AMD and Intel CPUs:


The Test

The SilentFlux was tested on an Asus P5WD2 motherboard P4 Motherboard Test Platform with a modified Pentium D 805 to read CPU case temps (both supplied by Directron).


Case Temp

Ambient Temp


On-Die Temp¹

SilentFlux, 2311 rpm, <50 dBA²





¹MBM on-die temperatures.
²50 dBA measured 8″ from the fan intake corresponds to about 30 dBA measured 3 feet from the fan, a very quiet noise level.

Results place the SilentFlux in the lower rank of heatsinks tested to date (Heatsink Ranking). Noise levels are very low.


While not for aggressive cooling, the SilentFLux is an interesting heatsink and a good solution for quiet cooling without adding pounds to your case.

Thanks again to Directron for sending this our way to test out.

Disclosure: Joe Citarella has a financial interest in a company developing thermosyphon products for electronic chip cooling.

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