Reply To: Tips & Tweaks: Lx3, Lx4, Lx5 modes

[Harrumph]

I assume you mean for optimized mode? Optimized output should be 427 for Genesis, but it also uses 256×224 mode for some games, in which case the output is 341. Remember you also have to adjust sample phase.
If you use generic mode instead, the output should be a multiple of 390.