Thermalright SLK800

Top rank Socket A heatsink — Joe

SUMMARY: Top Rank socket A cooling, depending on noise preference.

A while ago we took a look at the Thermalright SLK600. It’s not a stretch (actually, it was) for Thermalright to come up with an 80mm version, the SLK800.

You’ll get some idea of its size with Vantec’s 80mm Tornado fan in the background. The base

is about the same as the SLK600. The base finish is very good – there are no polishing marks on it, although not a polished finish; lapping might improve performance a tad but I think not worth the effort.

One notable factor in the SLK800’s favor is the amount of air flowing down through the fins from the 80mm fan overhanging the heatsink’s sides – the top measures 53 x 82mm. There is a significant secondary cooling benefit as a result, and components around the heatsink should run cooler. In addition, since the motherboard acts as a secondary CPU heatsink, there will be a positive impact on CPU cooling.

The clip mounts on all three of the socket’s lugs – a plus. However, you must use a screwdriver to engage the lugs. I found the clip very stiff and had to push down with my thumb along with the screwdriver to mount it on the socket. As with all screwdriver-assisted mountings, make doubly sure the screwdriver tip is securely in the clip’s slot – a slip under pressure could trash a motherboard.

Readers have been asking for a range of fan speeds when I test heatsinks, so I tested the SLK800 with Vantec’s Tornado, a Sunon 80 x 38mm fan, model #PMD1208PMB1-A rated at 84.1 cfm @ 5700 RPM, 55.2 dBA, 9.1w; this fan features vanes in the base to straighten airflow off the blades. I varied voltage to get a range of fan speeds and measured rpms using an Omega digital techometer.

I measured noise using a Radio Shack sound meter placed 8″ from the fan’s intake and recorded noise at a number of rpms – these should not be far off the mark far other 80mm fans at similar rpms.

Manufacturers meter sound at 3 feet from the fan, so the dBAs I measured do not correspond to the manufacturers ratings. I normalized the readings I found to the manufacturer’s spec for the fan, as shown in the table below.

The SLK800 was first tested on the CPU Die Simulator which gives results that are unaffected by motherboard influences. I then tested it on an Iwill KK266+ and Shuttle AK31, which are modified to read AMD CPU die temps directly, as an example of what users might see on their systems.