As you note though, VICE has an option to just lock itself to one frame of output = one frame of input. So even if you adjust the Pi to put out 50 that's still not quite the perfect rate.

So a real machine actually puts out about 50.13 frames per second. Possibly you'll still get the odd frame that goes slightly askew because cross-platform libraries rarely tie neatly to platform-specific signals like retrace.ĮDIT: with a little more research on the C64 specifically, one frame takes 19,656 cycles (312 lines of 63 cycles), but the machine is clocked at around 985,248.6111Hz (it's 17.734475Mhz divided by 18). On your Raspberry Pi, modify your config.txt for 50Hz if you haven't already. But because nowhere is it exactly written that 5 frames shall be output in 6 slots you also might be seeing some minor timing differences pushing one or the other frame backwards or forwards during the time that 50Hz and 60Hz end-of-frame timings are close. So you're probably not even getting as nice a conversion as a bad 24 to 25 - for C64 frames 1 2 3 4 5 6 7 8 9 10 you'll at best be getting output of 1 2 3 4 5 5 6 7 8 9 10 10. Neither is doing anything in particular in regard of the difference. Your Mac or Pi is pushing a new HDMI or composite image 60 times a second. Therefore the software is pushing a complete new frame 50 times a second. The simplification applied by almost all emulators is to calculate an entire frame of the display, output that, calculate the entire next frame, output that, ad infinitum. Your Raspberry Pi is most likely also to be running at 60Hz. Macs with a built-in screen are generally locked to 60Hz.

Mac gold digger emulator