Today we’re reviewing a waterblock for RTX 4090 Palit GameRock and Gainward Phantom graphics cards, produced by Alphacool. This waterblock is labelled “Core Geforce RTX 4090 GameRock Phantom with Backplate” and is available directly from Alphacool’s website for a price of 199.98 euros.
This is the new Alphacool CORE version, whose CORE 1 CPU waterblock we have already tested. Another version of the waterblock we’re testing today is available in the Eisblock range at a price of €159.99.
Thanks to Alphacool for providing us with a copy of this CORE RTX 4090 waterblock.
[nextpage title=”Unpacking: “]
Let’s start by opening the package we received from Alphacool. The box containing the waterblock arrived in a cardboard box, perfectly protected to avoid any inconvenience during unpacking.
Alphacool’s packaging is very attractive, and the small box contains very little information. On one side we find the series to which the waterblock belongs, the “CORE GPU BLOCK”, and on the other, two finishes that can be ordered for this series. The packaging is minimalist, with just the minimum of information printed on the raw cardboard.
Once the packaging is removed, we find a black cardboard box containing all the components needed to install this liquid cooling system. The first item we come across is the full-colour installation manual, translated into three languages: German, English and French. The instructions are very clear and are also available directly from the Alphacool website.
Next up is the waterblock, already equipped with its backplate, and a box of accessories. In the latter, we’ll find the screws, a tube of the brand’s APEX thermal paste, a wrench and two plugs for the waterblock, plus three pouches containing the thermal pads in different thicknesses (1 and 3 mm).
The waterblock and backplate are protected in film. No risk here, everything arrived in perfect condition.
[nextpage title=”The waterblock: “]
Alphacool continues in the tradition of the Eisblock waterblock for RTX 3080 FE with a monobloc configuration. This time we have a single acrylic plate, and the design has been simplified for this CORE version. Water passes over the first pane to go directly onto the chip. It then passes over the sides to cool the memory and power stages before reaching the outlet.
The dimensions of the block are 146.99 x 217.91 x 32.12 mm. As usual with waterblocks, no end caps are available. You’ll need to buy them independently and make sure it’s compatible with the G 1/4 thread. Two small triangles indicate the liquid inlet and outlet. But why 4 “holes”, simply to better manage your cooling loop.
The overall design of this waterblock exudes quality, and the design of this Core series takes Alphacool upmarket. We regret, however, that manufacturing takes place in China when competitors still produce in Europe.
The backplate supplied is made of aluminum, in black, and at last benefits from a refined, sober design. We note that the latter rises around the fittings, but by chance it passes around fittings 10/16.
The Alphacool waterblock also boasts RGB backlighting, which you can configure to suit your needs. The LEDs are evenly distributed throughout the block. The power plug is a 5v model that you can connect directly to your motherboard.
[nextpage title=”Installing the waterblock: “]
Removing the cooling system :
Now it’s time to install the Alphacool CORE RTX 4090 waterblock. Note that we’ve already carried out a series of benchmark tests. The idea is also to record the temperatures of the various components of our Gainward RTX 4090 phantom. Before installing the Alphacool waterblock, we need to remove the original cooling system from our graphics card.
Here, the task is much simpler than on the RTX 3080 FE, as we first need to remove the 11 screws from the backplate.
Next, remove the eight screws from the PCI bracket.
All that remains is to remove the 4 screws around the GPU chip and remove the PCB without forcing it, using gravity. There are still 2 cables to disconnect and you’re done.
Clean with IPA alcohol and you’re done. To remove traces of thermal paste, you can use a charcoal eraser. This also works well for cleaning anodized aluminum radiators stained by thermal paste.
Installing the waterblock :
Let’s move on to waterblock installation. The first step is to fit the thermal pads and then spread the thermal paste over the chip.
Next, place the PCB on the waterblock and gradually tighten the crosswise screws. At this stage, it’s best to dismantle it again to check the application of the thermal paste.
Here, the application as described in the instructions was not optimal, as can be seen in the image below.
I therefore reapplied some thermal paste. Alas, this was not conclusive, as the first tests produced poor results.
So I disassembled it again and squeezed the thermal pads as hard as I could with my finger. Then I did a cross application. The gain was over 6°C on the CPU and 1°C on memory. The 1mm thermal pads offered by Alphacool in the bundle seem too thick. You might want to consider replacing them with 0.5mm or 1mm ultra-soft ones.
If all goes well, we can reassemble and fit the thermal pads and backplate. The PCIe bracket is placed between the PCB and the backplate.
The waterblock is now fitted. This makes the board very compact. It’s perfect for use in small SFF configurations. The only problem is that the backplate protrudes enormously. This makes it impossible to access the locket on the motherboard. A notch in this area would have been welcome.
[nextpage title=”Comparative tests: “]
As we said, the idea is to be able to judge the impact of a liquid cooling solution against the original cooling system of our Gainward RTX 4090 Phantom.
The comparative tests will take place in two parts. First with the card at “stock” frequencies and then we’ll push the frequencies with the 666W Galax HOF Bios.
Performance at stock frequencies:
Here’s the table of our results with the stock cooling system and the Alphacool CORE RTX 4090 waterblock. This first table compares the performance of the cooling systems on 3DMark benchmarks where we’ve run a run three times in a row. The idea is to see how the temperatures behave, but also whether the Boost frequency increases if the cooling is better.
During our tests, the temperature in the lab was around 27°C. Well, not surprisingly, temperatures are excellent with the liquid cooling system, even if in terms of performance, there’s not much difference given the performance of the original air cooling.
As we can see, the performance of this Alphacool CORE RTX 4090 is spot on. The gain in GPU temperature is between 7 and 17°C, which isn’t bad at all. We regret, however, that the contact with the chip is not perfect, as it would be possible to have less than 15°C difference between the water and the GPU at 450W, compared with 20°C here.
Overclocking performance:
To push things a little further, we wanted to measure overclocking capabilities with this liquid cooling. We therefore compared performance on 3Dmark with and without overclocking using the Bios 666W Galax HOF for RTX 4090.
No miracle here, the chip doesn’t even manage to reach the power limit here, even at 1.1V. The very low temperature also helps to avoid frequency variation and therefore better performance. For power consumption over 535 W, we stayed below 27°C in relation to the water, which is still acceptable.
Now, bear in mind that switching to liquid cooling comes at a cost. You’ll need to invest not only in the waterblock, but also in a liquid cooling loop.
[nextpage title=”The last word: “]
We’ve come to the end of this test and I can say that I’ve been looking forward to this waterblock. The design and performance didn’t displease me, but it’s still not up to my expectations. A change of thermal pads to Alphacool’s Ultra soft 3W/mK is on the cards.
WB Alphacool CORE Geforce RTX 4090 GameRock Phantom with Backplate
We liked :
- Alphacool’s high-quality packaging
- Very detailed, full-colour instructions
- Waterblock finish quality
- The design of the CORE range
- Acceptable price with backplate
We would have liked :
- A notch in the backplate to access the PCIe locket.
- Ultra-soft thermal pads in bundle
- Better GPU contact and performance
- A waterblock made in Europe
Alphacool’s waterblock is the only solution for cooling Palit GameRock and Gainward Phantom RTX 4090 series GPUs. Although contact with the GPU chip is not optimal, it manages to keep it at less than 20°C compared with water at 450W. The attention to detail is also noteworthy, with the new, visually pleasing design of the CORE series. It could have been a flawless performance and deserved a platinum rating, but there’s still room for improvement!
