GPU Waterblock Test, including TEC version – Joe
SUMMARY: Very good choice for GPU cooling.

The good guys at Swiftech were nice enough to send an MCW50 GPU Waterblock to test.
Swiftech MCW50 features
- Push fittings for 1/2″ OD tubing
- Pin fin copper base
- Mounting hardware for a wide range of GPUs, such as ATI ® Radeon ™ 9000 to 9800 and NVidia ® GForce ™ products
- Designed to be used either in straight liquid cooling configuration or in conjunction with a thermoelectric (Peltier) cooling element
The base is typical Swiftech:

Very flat – do not try lapping this as you will only make it worse.
Parts shipped with the MCW50 should be sufficient for just about any situation:

Overall, very good build quality.
The Swiftech MCW50 was tested using the CPU Die Simulator and Waterblock Test Rig.

Waterblock | C/W | Pressure Drop – psi | Pressure Drop – inches H2O |
Swiftech MCW50 | 0.18 | 0.26 | 7.2 |
Unrounded data: 0.178 C/W with 0.0023 std dev.
Test Results indicate that the Swiftech MCW50’s pressure drop (or head loss) across the waterblock is very low; resistance such as this means that Swiftech MCW50 will perform nicely with moderate power waterpumps, especially if other components in the system are not overly restrictive.
I found that performance degraded by about 0.7ºC with at a flow rate of 0.5 gpm and improved by about 0.6ºC at 1.5 gpm – very “even” results.
For a comparison of the Swiftech MCW50’s performance to other waterblocks tested to date, see Overclockers.com Waterblock Test Results.
Swiftech’s MCW50 Waterblock is a fine choice for GPU cooling. As GPU waterblocks are usually fitted in series with a CPU waterblock, low flow resistance is particularly important for a GPU waterblock. Note that this waterblock is 1.22″ high, so plan accordingly.
Thanks again to Swiftech for sending this our way. The MCW50 is available from the Heatsink Factory.
SUMMARY: Very good choice for aggressive GPU cooling, but only for experienced users.

The good guys at Swiftech were nice enough to send an MCW50-T GPU Waterblock to test.
Swiftech MCW50-T features
- Push fittings for 1/2″ OD tubing
- Pin fin copper base
- Mounting hardware for a wide range of GPUs, such as ATI ® Radeon ™ 9000 to 9800 and NVidia ® GForce ™ products
- 80 watt thermoelectric (TEC, or Peltier) cooling element
- Foam insulation for condensation control
The TEC is fitted between the copper base and waterblock; the base is typical Swiftech:

Very flat – do not try lapping this as you will only make it worse. Note that the foam skirt around the base is there to control condensation – this is covered in the accompanying instruction sheet. In addition there is a foam pad to place on the back of the video card.
Parts shipped with the MCW50-T should be sufficient for just about any situation:

Overall, very good build quality.
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Effectively using a TEC involves more than simply slapping one on and running it. I strongly advise anyone interested in using this product to carefully read all the items HERE. In particular, Swiftech notes that:
- “The combined amount of heat (TEC + GPU) added to the circuit by the MCW50-T is approximately 115 watts (392 BTU/hr).
- The thermoeletric module pulls approximately 6A at 12 volts. When connecting the MCW50-T module to an existing power supply, users should verify their power supply current rating for the +12 volts line.
- [The MCW50-T] will dissipate 53 Watts continuous thermal load to ambient temperature.”
As I tested this unit, I noted that the heat load was considerably higher and I had to cool much more aggressively than for a waterblock without a TEC (no surprise). I also tested with a separate 12 volt power supply – a practice I highly recommend when using a TEC in any system.
I also want to point out that the load you can place on any TEC is limited. If you exceed its capacity, you will find that the TEC will run wild; that is, temps will continue to increase in a destructive heat loop. A safe, conservative operating guidline is to not exceed 50% of the TEC’s rating – in this case, 40 watts. In this instance, once I went over 50 watts, I started to see temps continue to creep up. At 70 watts, it started to get scary.
The Swiftech MCW50-T was tested using the CPU Die Simulator and Waterblock Test Rig. In this case, I will not report a C/W as it has no meaning when using a TEC, but show the delta T I achieved at 40 and 50 watts.
Waterblock @ watts, gpm | Die Temp Diff to Water |
Swiftech MCW50-T @ 40 watts, 1 gpm | -8.1 C |
Swiftech MCW50-T @ 50 watts, 1 gpm | 1.6 C |
Swiftech MCW50-T @ 50 watts, 1.5 gpm | -2.8 C |
It was interesting to see the increase in performance by increasing waterflow through the waterblock; high efficiencies are key to extracting maximum performance.
Swiftech’s MCW50-T Waterblock is a fine choice for very aggressive GPU cooling, but I caution that TECs are tricky animals to tame. As GPU waterblocks are usually fitted in series with a CPU waterblock, in this case low flow resistance is VERY important; maximum performance may require a separate cooling loop.
Thanks again to Swiftech for sending this our way.
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