Regarding the Strix 3090 and 3080 (oc or not), there is an issue with what seems to be all of them, where the shroud will buzz when the GPU reaches a certain temp and the fans reach a certain RPM, looks like ASUS are now aware and asking for details for the people effected (basically everyone with these cards, a few don't have the issue), so be aware, at around 72% fan with a temp of around 70deg, it will buzz, and its really really really annoying.
Example seen here from another card owner:
Luckily I undervolted my card so temps or fans never reach those numbers, but still.
My 3090 Strix Oc has been collected today for RMA due to this exact issue , well mine was the right hand fan making a racquet when going above 70% and made some strange buzzing noises briefly when dropping under 70%. My Ek waterblock is on its way to me so yeah i could have just fitted the block and be done with it but if i were to sell the card in the future then i would want it 100% working for its new buyer plus for the price it cost it should be absolutely perfect and nothing less so its gone back for a replacement which hopefully wont have the same issue

Good luck with the waterblock, hope that all goes ok.
, let us know how you guys get on 


