Sleeth 1 Waterblock

Waterblock Test – Joe

SUMMARY: OK choice for non-aggressive CPU cooling with moderate-high power waterpumps.


The good guys at PCCooler sent a their Sleeth I waterblock to test.

The Sleeth I features

  • Quick release fittings for 8mm and 10mm tubing
  • All copper construction
  • Mounts for Intel P4 and AMD Socket A/K7

The Sleeth features a mounting system which concentrates all force on the center of the CPU – much preferred to other mounting schemes. Note also that it ships with two sets of fittings for 8mm and 10mm tubing:


The base appears well finished:


There were no polishing marks apparent to the touch.

The mounting system includes mounts for Intel P4 and AMD Socket A/K7 CPUs:



The Sleeth I was tested using the CPU Die Simulator and Waterblock Test Rig.


Test Conditions: Inlet Water Temp: 28.5 C; Mounting force: 15 pounds; Heat Load: 70 Watts.




Pressure Drop – psi

Pressure Drop – inches H2O

Sleeth I




NOTE: These results are NOT comparable to tests done by others.
Unrounded data: 0.240 C/W with 0.0007 std dev.

Test Results indicate that the Sleeth I’s pressure drop (or head loss) across the waterblock is on the high side; flow resistance such as this means that the Sleeth I requires a moderate-large waterpump to maximize performance, depending upon how restrictive other components are in system.

I found that reducing flow to 0.5 gpm resulted in a performance decrease of about 0.7ºC and increasing flow to 1.44 gpm resulted in a gain of about 0.4ºC.

For a comparison of the Sleeth’s performance to other waterblocks tested to date, see Waterblock Test Results.


The Sleeth I Waterblock is an OK choice for non-aggressive CPU cooling. Flow resistance is on the high side and performance is fair; the Sleeth I will require at least a moderate power waterpumps (300 gph) for best performance, as long as other components do not unduly restrict waterflow.

Thanks again to PCCooler for sending this our way to test.

Email Joe

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