The Optimus 4090 block is designed to allow max cooling on the 4090 GPU die, VRAM and power delivery areas. Our XL Heatsink works as both a mounting system and a heatsink for the PCB itself.
Interestingly, our XL Heatsink allows for vastly better GPU performance than blocks with active backplates.
How is this possible? Because older-style blocks with low fin counts simply aren't able to dissipate the heat from the critical areas. Thus, the PCB itself heats up, and a rear active backplate is used to try and capture more of that heat. But with a correctly designed main block, the heat is dissipated at the source. This is why our blocks are able to beat active-backplated blocks by significant margins.
To back this up, we compared our Signature Kingpin 3090 block that featured a massive, solid copper active waterblock vs our XL Heatsink. The 3090 has rear VRAM and a 1000w bios, so the heat should be even higher.
But we found the real-world performance differences between our ultimate active backplate and the XL Heatsink were non-existent. This is because our main block's performance is doing exactly what it should - cooling the important parts - and any extra PCB heat is easily handled by the XL Heatsink.
If an active backplate improved performance, we'd make it. The good news is the Optimus 4090 waterblock makes active backs simply unnecessary.