There's no definitive rule for determining whether a card is using rhe reference PCB design or not, but generally, any card using the reference cooler (1) and m

There's no definitive rule for determining whether a card is using rhe reference PCB design or not, but generally, any card using the reference cooler (1) and most card SKUs released on a new GPU family's launch day will use the reference PCB design. As for why you's want the reference PCB for water cooling, well that is easily explained by looking at water cooled GPU heatsinks (2). A Graphics Card is composed of much more than the GPH itself. They basically stuff all the components of a mini computer (power management, memory, processor) onto a single board and each one of those subcomponents needs cooling in order to achieve optimal performance. A GPU heatsink that neglects the VRMs or memory will not be able to be overclocked as far as a GPU where those parts are actively cooled and in a liquid cooled system, there is typically very little airflow within the case. Slap an all-in-one water cooling system intended for a CPU onto a GPU and you'll often get memory issues right off the bat even with stock clocks and overheated VRMs will lead to throttling after a relatively short time in heavy use. The fans on a GPU provide enough direcf airflow to keep those components within spec, but remove the fans and replace them with nothing and you lose that necessary airflow. Since each card manufacturer uses their own PCB layout (once they figure out what to improve or lower costs on versus the reference design), there is no way to guarantee a heatsink will work with anything but the reference design. Card manufacturers place their VRMs all over the place and sometimes even stray from spec in memory placement so heatsink manufacturers can't standardize on anything but the one design guaranteed to have a market presence which is the OEM reference PCB. 1* Here's an article covering an old Nvidia reference cooler design: https://techbuyersguru.com/founders-edition-vs-open-air-video-card-coolers-definitive-analysis https://techbuyersguru.com/founders-edition-vs-open-air-vide... 2* Here's a GPU water heatsink: http://www.phanteks.com/PH-GB1080.html http://www.phanteks.com/PH-GB1080.html