Thermalright SLK 900A

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Very good Socket A cooling, depending on noise preference – Joe

SUMMARY: A fine choice for Socket A cooling, although performance will depend on each user’s noise tolerance.

Thermalright 900A

The good guys at Thermalright were nice enough to send Thermalright’s 900A one for a test spin. This version features a return to the “basic” mounting clip, one which engages all three socket lugs; it also requires a screwdriver to mount. The clip is very stiff, so use care when mounting on a motherboard – one slip can trash the mobo.

The base is well finished:

Base

When I ran my nail over it, I could not feel or hear any ridges.

THE TEST

The Thermalright 900A was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. For testing, I used a Delta FFB0812SHE, 68 cfm @ 4800rpm, 48.5 dBA; this features vanes in the base which straighten airflow into the heatsink. I varied rpms to give a range so users can match performance to noise tolerance.

Graph

TEST RESULTS – CPU Simulator

Heatsink
Die Temp
Ambient Temp
Delta
C/W
Thermalright 900A, 4819 rpm
43.9 C
27.4 C
16.5 C
0.24
Thermalright 900A, 3504 rpm
45.9 C
27.4 C
18.5 C
0.27
Thermalright 900A, 2009 rpm
51.6 C
28.7 C
23.4 C
0.34

Delta = CPU temp – Ambient Temp
C/W = Delta / CPU Watts

Interpreting C/W: For every watt (CPUw) that the CPU
consumes, the HSF will limit the CPU’s temperature rise to (C/W x CPUw)
plus the temperature at the HSF’s fan inlet. For example, at an ambient temp of 25 C, a C/W of 0.25 with a CPU radiating 50 watts means that CPU temp will increase 50 x 0.25 = 12.5 C over ambient temp, or 37.5 C. The lower the C/W, the better.

Die Simulator results place the Thermalright 900A in the topmost rank of heatsinks tested to date (Heatsink Ranking).

CONCLUSIONS

Thermalright’s Thermalright 900A is a fine choice for Socket A cooling, although performance will depend on each user’s noise tolerance.

Thanks again to Thermalright for sending this our way. The Thermalright 900A is available from Crazy PC and Heatsink Factory.com.

¹Note that manufacturers measure fan noise usually 3 feet from the fan.

Email Joe