XMP lowering clock speed+perfomance on Ryzen 7700X

Motherboard form factor isn't relevant.
AsRock says B650i Lightning WiFi has 8+2+1 60A Dr.MOS, which should be more than enough for 7700X.

Are those 60/70 -> 85C CPU temperatures? If so, wow, I would NEVER run anything I own that hot.

I'm a reliability nut. I NEVER enable boost on any of my CPUs, and 100% of my PC builds for myself use ECC memory. I run my 9800X3D with boost disabled, meaning, it tops out at 4.7GHz, which is plenty fast for me. I don't like giving even 1.1V to any of my CPUs, and prefer to keep them under 1.0V. Obviously, I'm not a good reference point.

Note, negative offset on a CPU that really can't deal with it will reduce performance because it will activate clock stretching. Instead of crashing, it stretches clock period to slow things down, so it doesn't crash.

I never do XMP/EXPO because all memory I buy are unbuffered ECC memory, which are all JEDEC only. But do check if enabling it affects FCLK / UCLK.

I think 2000MHz FCLK and 1:1 ratio is safe. I actually had to manually restore them after 3.20 BIOS update on my B850M-X. Originally, it defaulted to that, but after the BIOS update, it went down to 1750MHz FCLK and 1/2 speed UCLK (1400MHz). That's ridiculous. I forced it to 2000MHz FCLK and 2800MHz UCLK (for my JEDEC 5600MT/s memory). Stupid BIOS.

Anyway, get HWiNFO64 and check your settings, as well as see if it's thermal-throttling.