Why XEL hashrates on 3090 is lower than 3080 Ti?

[i1itione]

Does it mean 3080 Ti not just a cheaper version of 3090? It is actually more powerful than 3090 at some point?

[rigelminer]

I experimented a bit and it turns out 3090 loses a lot of performance relative to 3080ti when you set mem offset to -1000. If you keep it zero, lock at 5000 or apply a positive offset to both cards their hashrates are in line with what's expected.
I don't know why a negative offset affects those cards differently, so maybe just don't set mem to -1000 on your 3090.