I've checked EKWB but their waterblocks don't appear to cover the VRMs. Are there any that do since the 12900K is slated to draw a lot of power when over clocked, or are 21 mosfets deemed adequate for staying cool, even when drawing 105A?
You're referring to a monoblock such as the one present on the Extreme Glacial. Adopting early means this is likely your best option until more products come to market.
Regardless of what board you have the MONOJUNK is a waste of time. The only block I ever found that cooled the VRMS without compromising the CPU was using two different blocks on a R6E. Heatkiller makes a VRM block for that board and it worked great. MONOJUNK cools the VRMs just fine but they suck at cooling the CPU. Tried several over several boards and always the same result. Last one was for the R6EE. They said it had a new cooling engine. Well new or not the VRM temp did stay at a constant 35C but the CPU temps under heavy load went up 10C. Yanked it back off and staying with the stock heatsink that's a big old chunk of metal and I've yet to pass 50C on the VRMs under heavy loads for an extended period. Typically I don't pass 40C, Right now sitting at 36C.
It would be nice to see more VRM blocks but theres just not much of a market for them. People buy the MONOJUNKS for the aesthetics because it certainly cant be for performance.