TLDR: if you’re wondering if the RX 6400 can run idle memory clocks on high refresh screens (1440p@144Hz), it can’t.
Had multiple monitors for a long time, high refresh rate. These setups trigger something in the driver (both NV and AMD), that keep memory clocks in an engaged state (can’t idle).
My 6800XT was running 1800MHz memory clocks all the time due to this (and 2070 Super before that). Bough a used Radeon WX 3100 out of curiosity and swapped my 2nd monitor to it. The 6800XT finally knew peace. However, the WX 3100 couldn’t handle a single (1440p) 144Hz display and its memory clock couldn’t idle. Dropping to 120Hz was enough.
I ordered a 6400, just to have something from the same family with the 6800XT as the second card. I expected that it could run 144Hz with idle mem clock, being newer in every way basically, but no. 144, 120, 100Hz kept mem clock @ 1078MHz. Only dropping to 60Hz was it able to idle.
Not sure if it would work different on a 1080p screen. Dunno if this only bug me, thought I’d share.
