Hot-headed unicorn under water – Alphacool Eisblock Aurora Acryl GPX-N for Nvidia RTX 3090 Founders Edition | Modification and practice test
Anyone who, like me, was able to purchase an RTX 3090 Founders Edition (FE) for the launch at the EIA, can’t really complain. Plenty of performance for 144 FPS in most games even with the highest graphics settings and, if we’re honest, the increase in value of over 50%, of course, add to the appreciation. But, as is so often the case, there are also negative facets, in this case the cooling and especially that of the GDDR6X VRAM.
Nvidia has done everything possible for Ampere to make the Founders Edition cooler as powerful and efficient as possible. 3 slot design and even a trimmed circuit board for better airflow are probably the most distinctive features of the RTX 3090 variant. And for the most part that works quite well for a Founders Edition, only with up to 400 W TGP, which the pixel accelerator is allowed to approve ex works, the physics soon reaches its limits.
Boiling GDDR6X despite 3-slot cooler
This is noticeable on the one hand in the background noise of the fans, which have to run at over 70% of their maximum speed at full load in order to keep the heat in check, and on the other hand in the temperatures of the GDDR6X. As Igor pointed out shortly after the launch, the memory at Ampere is also a thirsty competitor and accounts for a significant proportion of the card’s total power consumption. The cooler for the glowing memory modules from Micron should then be correspondingly powerful.
Intended conjunctively, because while a pad mod was still available on the 3080 and thus the backplate for cooling the memory on the other side of the PCB could be added, this space is already occupied on the 3090, by the second half of the 24 GB of GPU memory. Nvidia did not save on thermal pads with the 3090, but the few square centimeters of anodized aluminum backplate are already overwhelmed after a few seconds of full load with this number of memory chips and only a drop on the hot board without active airflow.
As an example, I started a memory-intensive task here by doing a bit of Etherium mining. Even if the excavator mining software can only allocate 8 GB of the VRAM, i.e. graphics memory, by default, and the GPU itself is only partially used, the deficit of the cooler becomes apparent after a few seconds. In HWInfo, which has recently been able to read out the GPU memory junction temperature, we see the 110 ° C maximum temperature after a few seconds, as specified by Nvidia and Micron, the TJmax as it is known from CPUs.
Even if the fans switch to hysteresis here and resemble the background noise of a vacuum cleaner at 100% speed, your effort is in vain, because the airflow of the fans never reaches the VRAM. The temperature does not go above 110 ° C, but only because the main memory is now automatically clocked down, at the expense of performance, of course.
Mining is a very memory-intensive use case, but here, too, just a third of the 24 GB VRAM of the RTX 3090 was allocated and thus utilized. The picture is correspondingly similar in gaming or in 3D benchmarks. As a reproducible and representative use case, I tried the 3DMark Port Royal today and let it loop for 10 minutes per test run. The test settings are +100 MHz core, +1000 MHz memory, maximum temperature and power limits of 90 ° C and 115% and the standard fan curve.
If you make a hasty judgment and attribute the excessively high heat load to overclocking, I will unfortunately have to disappoint you. The RAM needs a few watts less and a few seconds longer to warm up in stick mode, but the maximum temperature remains the same. Actually also logical, because the backplate remains a dead end for heat dissipation without airflow. To be fair, it has to be said that the GPU memory junction temperature can only be read with an accuracy of 2 ° C, due to the technical characteristics of the GPU. In this respect, the difference between stock and OC could also be in the area of a measurement error.
The bottom line is that the result remains the same: While the GPU levels off at an acceptable 70 ° C, the memory also reaches the 100 ° C mark after a short time in the 3DMark Port Royal and stays there. It is also interesting that the standard fan curve brings with it a certain inertia and the fans only switch to their final operating speed as soon as 100 ° C storage temperature has been reached – again keyword hysteresis.
It’s just stupid that the memory doesn’t get any of this higher potential cooling performance, as it never gets there. The GPU itself gets cooler, but actually there is no real reason for it, because at almost 80 ° C it is actually still within limits. Conversely, the noise emissions are unfortunately significantly higher – the result: You can hear the fan humming through headphones and game sound, which can be quite annoying.
Long preface, in a nutshell: Another cooler for the RTX 3090 Founders Edition is needed! And this is where Alphacool comes into play, who kindly provided an ice block Aurora Acryl GPX-N RTX 3090 Founders Edition with backplate. Today we take a look at it in detail, mount it on that 3090 Founders Edition graphics card and then compare what the conversion has brought us in terms of cooling performance.