Overclock demo

Do you like to overclock your NES? Run this ROM and see how far you're pushing the CPU. And if you've figured out how to change the clock while the power is on, be even more amazed.

This is part of the NES POST project.


EDIT: It has come to my attention that the way I'm figuring cycles per line has some systematic error due to FCEUX sucking at timing when the 9 sprites bit is activated. I have updated the ROM.

Machine has a Brazilian M-PAL clone discrete PPU (same timing as NTSC but outputs color information in PAL standard), UM6548, clocked at 21.453666Mhz(3.575611Mhzx6).

@29.498928Mhz:

Dendy-esque UMC CPU


Legit RP2A03E


Using the legit RP2A03E CPU with the NTSC clock:


With M-PAL clock:

Dendy (6527P/6538 chips):



So, this old researches by HWM are confirmed again.