Thermalright SK6+

Solid performer – Joe

SUMMARY: Another solid performer from Thermalright.

SK6+

The kind folks at Thermalright were nice enough to send a sample of their latest heatsink, the SK6+. This is similar to the SK6 but heavier – the SK6+ weighs in at about 400 grams while the SK6 is 330 grams – more copper for better cooling performance.

The base is well finished:

Base

When I ran my nail over it, I could barely hear, but not feel, the polishing marks. The clip engages all three heatsink lugs although it requires a screwdriver to mount. The SK6+ ships with two sets of clips to mount 25 mm and 38 mm fans, as well as a tube of thermal grease:

Parts

In summary, a copper heatsink with a secure clip (screwdriver needed).

THE TEST

The SK6+ was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. I then tested it on a Shuttle AK31, modified to read AMD’s on-die diode, as an example of what users might see on their systems.

The fan I used was a Delta 60, Model #FFB0612SHE – a 60 x 38mm unit rated at 43 cfm @ 7000 rpm, 50 dBA. I varied voltages to develop a range of rpms and C/Ws so readers can evaluate performance with different fans. I measured noise at various rpm settings, as noted below:

TEST RESULTS – CPU Simulator

Heatsink
Die Temp
Ambient Temp
Delta
C/W
SK6+, 7122 rpm, 50 dBA
41.0 C
22.2 C
18.8 C
0.28
SK6+, 5992 rpm, 47 dBA
42.1 C
22.6 C
19.5 C
0.29
SK6+, 5000 rpm, 43 dBA
43.9 C
22.9 C
21.0 C
0.31
SK6+, 4012 rpm, 39 dBA
45.7 C
22.7 C
23.0 C
0.34

TEST RESULTS – Motherboard
CPU/Motherboard

CPU Die Temp

Ambient Temp

Delta

C/W

CPU Back Temp

XP @ 1467, Shuttle AK31

42.5 C

23.9 C

18.6

0.29

33¹ C

¹In-socket thermistor per MBM

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 SK6+, with the ultra-noisy Delta 60, in the top rank of heatsinks (Heatsink Ranking). Less noisy settings lower performance a bit (as expected), but still very credible cooling.

The difference between a screaming 7000+ rpm and a tolerable 4000 rpm is 6 C. Users might consider using a rheostat or a temperature controlled fan to moderate noise as requirements dictate.

CONCLUSIONS

Thermalright’s updated SK6+ is a very competitive entry. Performance scales nicely with rpms, so tradeoffs between performance and noise are predictable.

Thanks again to Thermalright for sending this our way.

Email Joe

Be the first to comment

Leave a Reply