As mentioned in another thread, I’m not familiar with DDR5 Micron ICs, but you could always try to tighten tRFC a bit and increase the tREFI a lot, depending on the temperature of your system. However, I'm not sure if ECC error reporting will still accurately work then.
Personally, I've never overclocked any ECC memory, mainly because in the past it was only supposed to work at the exact speed the sticks were specified for. Maybe I'm just getting old, or it's different with DDR5, since Kingston happily sells overclockable reg. ECC kits these days, but I would definitely test not just for stability, but also if ECC still works after tightening timings or changing clocks.
The last ones I really overclocked for daily use was a set of Crucial DDR4-2667 DIMMS that ran happily at DDR4-3200 with a bit of a voltage bump. The real 3200 was a bit more expensive at the time so I opted for cheaper 2667 and did some experimentation.
If you are going for improved energy efficiency, you can probably reduce the PPT of the 7950X down into the 160W to 200W range without loosing much performance, or even go full eco-mode, aka the 142W PPT preset like the mid-range Ryzen 7000s. I locked both my 7950X's to 85°C and 200W without noticing much of a performance loss in real world applications, but they run a decent bit quieter without the fans ramping up for those annoying load spikes above 215W. I'm using AIOs with a quiet fan curve for them, though.
Right now I have that NH-D9L cooler so I might restrict the power level a bit. Running stock I just finished a Linux test zipping one of my VM's for 45 mins at 5GHz peaking 96c (230-ish watts) while listening to some random youtube 80's classic mix and browsing for how to get temp status. Just as just YT starting playing a-ha "Take On Me" I stopped the zipping because it was taking too long and the dumb compress dialog can't or won't show progress, then shortly my wifi card failed on the cooldown cycle.
Just then I was feeling nostalgic for Windows, 7zip dialog, and HWiNFO64 because it all just works.
The switch is painful.
I'm starting another test. It seems 7zip is only pulling 200-ish watts (total system power) @80c. Adding YT Foreigner "I want to know what love is" pushes it to 230w 96c but at least I can see my zip progress now. RAM is pushing 54c. I think my VRM temp is around 60c but no specific sensor named VRM so I can't be sure.
( edit )
Test 80% complete
It seems I'm right in the ballpark for frequency and temperatures with this little air cooler.
With the default voltages set from my RAM after quite a bit of testing my infinity fabric speed tops out at 2166 (2200 no post) and RAM at 6200MT/s (6400MT/s will reboot after a short time).
Keeping MCLK=UCLK and FCLK 2:3 ratio I land at the following configuration without changing any timings.
2800-2000-2800 => 3100-2066-3100
OCCT's benchmark shows a bit of improvement
Reads
1,538.65 => 1,655.71
Writes
1,473.81 => 1,588.77
Comparing Thaiphoon Burner output it seems UEFI/BIOS memory training might be tightening up timings a bit?
I took out my old cheat sheet to see what the differences in timings look like in nanoseconds.
I reworked my spreadsheet a bit and I was able to squeeze in a nearly universal improvement in timings just by raising frequency and after making some manual corrections where UEFI was on AUTO. I should be able to use this as a guide to see how much I might be able to trim the timings at different speeds under 6200 at the current voltages I'm using and then take a look at the overall latency and choose which one has the best balance in latency and bandwidth. Well that's the theory anyway.