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Test of CpuFX’s waterblock — John “Hoot” Hill

Hoots Corner

When I wrote my previous article The Big Blocks on the Block, I mentioned that I had never gotten the promised Z4 from CpuFX for testing.

Word must have gotten back to them – when I got home from my trip to Chicago last Friday evening, the postman had left a box sitting on top of the three foot snow drift in my driveway. I waded into the garage, duffel bag and box in hand, slipped off my shoes in the mudroom and set it down. I had another pressing priority after the long drive.

Upon opening the box, inside was a very nice water block and mounting hardware. The Z4 had arrived.

First look

The Z4 consists of an aluminum carrier with a copper block employing a squared spiral channel.

Block Top

Picture courtesy of CpuFX.

Here’s the one I got in its final assembly state:


The 3/8" ID barbs are custom made by CpuFX from anodized aluminum and are sealed into the block with what appears to be an epoxy compound. No removing these babies. I thought the Blue for cool water in and Red for warm water out was a cute touch. The carrier in the above picture is aluminum, not brass – I have strange lighting in my room.

My 3/8" ID Silicone tubing fit the barbs very securely – no need for clamps. The copper base on mine was silver plated. It is secured to the carrier by four socketed, cap-head screws and sealed with the same compound as the barbs use. All-in-all, a very strong and secure device.

The finish on the base is very peculiar – you can see milling swirls, but they are so fine that you can not feel them with your fingernail, kind of like the reflection you see on a CD. I would not lap the base, mostly because it does not need it and partly out of fear of effacing the silver plating, whether it does anything for thermal conductivity or not.



The mounting method employs a bar that mounts on top of the motherboard. It has nubs that line up with the standard Socket A holes and nylon screws that go into the nubs from the bottom, to retain them. Then the spring loaded screws go into a tapped set of holes that are closer together than the standard Socket A holes.

This is a good departure from the conventional mounting methods because you can remove and re-install the block without having to remove the motherboard, such as with blocks that use a continuous screw all the way through. In the case of blocks that use standoffs, some people have trouble with the standoffs loosening up from repeated removal and re-installation. This bar system avoids that problem also.


Test results

I used the same setup described in my previous article. At 112 Watts, it
represents a typical overclocking scenario where no peltier device is used. As hard as I strived for repeatability, make no mistake: My results are anecdotal. That is to say, they are reproducible if you have the same hardware and the same environmental conditions as me. Here’s how the Z4 performed:

CpuFX Z-4




Air Temp

Case Temp

Inlet Water

Core Temp













Though not as finely finished as some other blocks I’ve seen, the Z4, at 112 Watts, did as well as the Swiftech MCW-462u in my system. The silver plated copper block looks nice, though I am reluctant to assign any performance value to the plating. It is solidly built and relatively easy to install.

John “Hoot” Hill


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