Zalman ZM-WB2 Waterblock

Waterblock Test – Joe

SUMMARY: Good choice for CPU cooling, especially with low-moderate power waterpumps.


Weight: 510 gr; Size: 64 x 31mm, ex fittings

The good guys at Zalman were nice enough to send a Zalman ZM-WB2 Waterblock waterblock to test; this is their first entry into the watercooling market. It comes packaged in a blister pack:


The Zalman ZM-WB2 features:

  • Three compression fittings for 8 x 10mm, 8 x 11mm and 10 x 13mm tubes
  • Anodized aluminum top, copper base
  • Mounting hardware for Intel Pentium 4 (Socket 478), AMD Athlon/Duron/Athlon XP (Socket 462) and Athlon 64 (Socket 754) CPUs

The compression fittings screw into the waterblock:


I would guess that if needed, users could substitute whatever fittings they wish, assuming the same thread. Removing the fitting shows an interesting array inside the waterblock:


It appears there are a number of round copper plates to increase surface area within the block.

The waterblock ships with enough parts so that it can be mounted on Intel Pentium 4 (Socket 478), AMD Athlon/Duron/Athlon XP (Socket 462) and Athlon 64 (Socket 754) CPUs:


Note that the mounting clip centers pressure over the CPU core – there is a dimple in the block to hold hte clip in place. I find that this is by far the best mounting system, as all forces are concentrated in the right place.

The base is polished to a mirror finish:


Overall, the build quality appears quite good and the included hardware should keep users current for some time.


The Zalman 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





NOTE: These results are NOT comparable to tests done by others.
Unrounded data: 0.174 C/W with 0.0009 std dev.

Test Results indicate that the Zalman’s pressure drop (or head loss) across the waterblock is low-moderate; resistance such as this means that Zalman does not need a large waterpump to extract maximum performance.

I found that performance degraded by only about 0.4ºC at a flow rate of 0.5 gpm and improved by about 0.7ºC at 1.5 gpm.

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


Zalman ZM-WB2 Waterblock is a good choice for CPU cooling. In addition, with low-moderate flow resistance, it will perform well with moderate power waterpumps, as long as other components do not unduly restrict waterflow.

Thanks again to Zalman for sending this our way, and greetings to all our readers in Bulgaria.


Email Joe

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