What case and fans do you have and what temps does the 3090FE hit?
My 3080 FE never goes over 66c. My case isnt expensive, Phanteks with 2 noctua 140mm intake fans and 1 exhaust noctua. All 3 are locked at around 42% (700-750RPM) so to keep noise down.
Case temps are always low
That's a similar setup to mine, I have a Fractal case in an open configuration with the same fan layout and a Dark Rock Pro cooler. (3090FE is too long to use the standard layout!). The 3090 is undervolted and never gets much above 65 degrees, even under full load. Fans rarely ever ramp up to where they're audible.
So I'd be surprised if my RAM was getting excessively hot.