I am so happy, with my cosmos II PC case. 11mm copper almost 30mm thick incl. backplate altogether. I fear you need a copper backplate and a copper water block top to to keep 4080/ 4090 cards at reasonable temperature. I am not a friend of plastics/ acrylics used in waterblocks. Can´t wait for a review. Edit: @sfdmark : I totally agree with you in any aspect, you can´t avoid acrylic, pom, or any other form of "plastics", I would have written better "synthetics" in a custom loop. And in fact, there is no qual. issues at all, if you look out for pure silence, no problem. My PC case is closed, I don´t care about LEDs, only a matter of taste. BUT: recently I have seen testing data of a 4090@550W with pcb temp. @ almost 70°C max..!! Imho, because of enormous cooling capabilities a GPU waterblock must have today, from OC perspective, it might be mandatory to use maybe even an active copper backplate for heat dissipation. EKBW charges €240.-, now depending on similar design, a passive copper backplate should´t add more than €10.- to price tag. Or maybe if they design clever enough, they can offer a "copper" upgrade sometime. Reviews will show And actually, in fact, today, imo, you can´t buy or pre-order anything without having someone look over it before.

First of all, sorry EKWB I like you but this block is not ready to deliver. Could be ready to go in production, aka you have made the drawings, but product is not ready for delivery. At least it is not atm while writing this. That was the case with my velocity 2 for ryzen 9 7950x, was "ready" for pre-order , I 've ordered one on October the 4th and still I don't have it cause it is delayed.

brogadget:

I am so happy, with my cosmos II PC case. 11mm copper almost 30mm thick incl. backplate altogether. I fear you need a copper backplate and a copper water block top to to keep 4080/ 4090 cards at reasonable temperature. I am not a friend of plastics/ acrylics used in waterblocks. Can´t wait for a review.

The acetal does not affect the cooling capacity at all and it is perfectly fine for long term usage. Doesn't affect the coolant or anything suspicious. One way or another the custom loops have a part that it is made from acetal. There is no need to pay almost double the money to get full cooper waterblock and also it won't have LEDS!!!! 😛