Tried a couple of different men splits (256/768 & 512/512) but it didn’t make a difference. I’ve actually given up for the moment…I’m keeping my eye out for an old CRT TV that I can hack a Pi into. At least I know this will remove 2 frames of lag, then I can start messing around with the settings again and see if I can reduce the lag some more.
There was another member here who was also experimenting with different settings etc to try reduce the lag, but I think he gave up on it too. He was using a RealTime kernel version of Raspbian. I tried this and as far as I can remember, it shaved off one more frame. The downside is that at the moment, overclocking isn’t recommended on the RT kernel image; the SPI isn’t synced properly so overclocking the Pi also overclocks the SPI (which could be bad news if you’ve got anything (i.e., the ControlBlock) hooked up to the GPIO).
I think I’ve just become overly-sensitive to lag in my old age (!). The last time I messed around with emulation was maybe 7 or 8 years ago when I had an Xbox1 hooked up to a CRT. Played loads of NES/SNES games on that thing with my mates and never really noticed the lag. Since I started messing with all of this I’ve tried emulators on my Mac, a Windows machine, and even dug out my old PSP, and they all seem to have some sort of lag that, to me, is very noticeable.
I dunno…if I make any more progress I’ll post back here, but I’ve got more important things to sort out first (moving house, for a start).