so what core/mem speeds should i set on my bios for 2d?

[d94]

okay, im setting my 3dmode to 420core and 850memory
i tested the settings with multips hours of half life 2 gameplay so im 100% sure they're stable. the question is, what speeds should i set the core/mem in the 2d mode?
btw, this is for my custom bios :)

thanks
-d94