I'm amazed how much performance gain I just got from tweaking these timings.
I went from AUTO to TRRDL-TRRDS-TFAW, 6-4-16.
It gained my nearly .1sec in super pi 1M. 7.6 down to 7.5.
In BFV, where I am usually CPU bottlenecked, CPU power consumption went up 10W from ~100W to ~110W.
As a result, the 4090 was able to stretch it's legs, going from ~320W to ~360W+
The most important benefit is the "smoothness" it brings to the gaming experience. It has to be experienced to explain it but it's no exaggeration to say that tweaking my memory timings has improved my gaming experience nearly as much as upgdrading to the 4090.