The big radiator material test: Between promise, reality and the forbidden – Water Cooling tested more in Detail! | Part 1

1 - Intro, Samples and Equipment 2 - Alphacool NexXxoS ST30 Full Copper X-Flow 120mm 3 - Aqua Computer airplex radical 2/120, Alu-Lamellen 4 - Bykski CR-RD120RC-TN-V2, D30 V2 Full Copper 5 - EKWB Quantum Surface P120M - Black 6 - Hardware Labs Black Ice Nemesis GTS - 120 XFlow 7 - Watercool HEATKILLER RAD 120-S Black 8 - Summary and Conclusion

EKWB Quantum Surface P120M – Black

Here it is, the letter E for EKWB and with it the Quantum Surface P120M – Black. This thing isn’t cheap and I’m really excited to see what’s on it, on it and inside it…

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Let’s let the manufacturer have his say first, as he emphasizes the design of the channels (“tubes”) and the copper cooling fins.

First of all: There is no copper “H90”. An addition of 10% brass (as in the case of Bykski) is NOT copper, but still an alloy, i.e. brass. Brass CuZN10, to be precise. Incidentally, it is interesting that I measured exactly this value. Just like the brass “H62” (correctly CuZn38) of the pre-chambers, where I then (logically) arrive at 38% zinc content, which corresponds to 62% copper content and which can suddenly be called brass again in marketing.

This presents us with a small paradox. EKWB was the only company to state the exact copper content of the alloys in the test, but shamefully concealed the fact that it was an alloy, at least for the channels. Copper H90 sounds better, of course, but there is no such thing. It’s either copper or it’s not. A little bit pregnant doesn’t work either. Too bad, because the rest fits! That wasn’t really necessary.

The results are quite interesting. After the table, which already anticipates and summarizes a lot, we now come to the test results including pictures and further details.

Pre-chamber / terminal and solder

Leaving aside the cuts caused by the separating tool, we see an average soldering quality. The rough edges at the ends of the soldered channels are likely to cause slight swirls, but it is still within the tolerable range. However, it is not “premium” either.

The solder is OK so far, but there is also a fair amount of oxidation of the solder.

What is noticeable in many places, however, is the rather high proportion of flux residues in the entire pre-chamber area. Sodium and potassium are unmistakable indicators of inadequate flushing. Nice is a bit different, “premium” too.

Now let’s take a look at the brass inside on the carrier plate of the cooling channels. The depth measurement in 16 layers shows the ratio of copper to zinc. However, as the depth increases, the proportion of copper decreases significantly. And again we also have the flux residues here, up to barium, which may come from wherever. I have not found any chlorine, so alkaline barium chloride is certainly out of the question. But neither is H62, i.e. CuZn38, at this point. The presence of potassium (K) and sodium (Na) leads in the worst case to alkaline contamination of the coolant, which should make thorough cleaning of the radiator unavoidable before first use.

The outside of this chamber, i.e. what the customer can see and touch, is, as we have already guessed, made of coated brass. That’s what it says in the specs. However, it is not “H62”, but even the better CuZn30, i.e. 70% copper with 30% zinc. The pre-chamber therefore consists of several different brass variants. You don’t have to understand it, but that’s the way it is.

Let’s move on to the soldered threaded inserts, which should actually only be made of brass for reasons of durability. Copper is simply too soft, so EK opted for the harder CuZn30 material, i.e. 70% copper and 30% zinc, just like the rest of the pre-chamber.

Cooling channels and fins

The most important part in the middle are the cooling channels and the fins, both of which the manufacturer specifies as pure copper. Let’s first take a look at the section as such. The channel carries the closed fins, which are arranged quite closely together.

Let’s take a look at the measurement of the cut channel and yes, it is exactly the advertised 90% copper and 10% zinc content, even if it is brass.

The cooling fins, which only show copper, look good. This was also stated and is therefore correct.

Housing and accessories

Finally, we come to the side panels, the stabilization and assembly, the light metal attachments and the enclosed screws. Let’s start with the panels. Hidden under the black powder coating is durable chrome-barium steel (60% Fe, 30% Cr, 10% Ba) from the 5th shot. The chromium content is very high and why barium is needed… Probably not for coloring. Or is it?

Which finally brings us to the screws…

… which are made of simple, galvanized steel. I have already commented on this several times, it is quite soft.

Plugs and adapters

Under the nickel we find CuZn42, a brass alloy with 58% copper and 42% zinc. You can leave it as it is.

Interim conclusion

The radiator is well made, you have to give EKWB credit for that, but the premium quality is a bit of a problem if you don’t flush it properly. And no, the ducts (“tubes”) are NOT made of copper, even if the copper content is quite high at 90%. Marketing beats facts, which is a shame, because you don’t really need that and the “H90” shows that you actually know better. The soft, cheap screws are not really premium either. The radiator looks nice, which at least puts the high price into perspective.