Hello, I own Legion 5 (15ACH6H) 2022 model with R7 5800h CPU. The BIOS is completely locked down; neither RAM or CPU settings can be adjusted. The few settings that can, are only adjustable through "Universal AMD form browser", but those are mostly completely useless either way (except for BGS alt, GDM disable, T1 command rate), but no way of adjusting Curve optimizer, RAM speed/timings or PBO offset.
Only way I found of getting better performance/efficiency is:
a) Increasing BCLK (really unstable above 101 MHz, the laptop screen shakes like crazy – prolly internal display port timing issues ?)
b) Tuning RAM via modifying SPD
I've been playing around with this tool https://github.com/integralfx/DDR4XMPEditor , trying to squeeze out the last drop of performance out of my 3200 MHz Gskill Ripjaws 32GB DDR4 RAM kit.
So far I've been able to get these timings:
Which is a great result, except I have no idea how to tune some secondary/ternary timings… Any lower primaries either don't boot or are unstable, frequency can be adjusted, but it doesn't affect the specific SPD entry that computer runs at.
1) tWR: I've read everywhere, it is supposed to be 2 * tRTP, or some other formula, but then others recommend 14, 12, etc. Main problem is that tRTP timing is not adjustable through SPD, so I have no possibility of both lowering tWR and still retaining tWR = 2 * tRTP.
I was testing both tWR 12 and 18, but neither seemed to improve bandwith nor latency, infact the results got somehow worse, but I have no idea if that was just Windows being grumpy. The test seems to jump all over the place depending on time of day and mooncycle.
2) tCCDL, this timing is almost nowhere mentioned online, it is supposed to be "CAS to CAS Delay Long". Changing this from default 8 to either 7 or 6, resulted in the timings tRDRD/WRWR SCL to decrease to 4. However from my tests, I have also measured small regression, especially in read speeds, so I can't really decide whether to lower it or not.
Ps. Bonus points for anyone who would look into unlocking Cezanne chips / BIOS to allow undervolting :3