Gameplay is not sped up (assuming the game is not in a constant state of some slowdown, to begin with, like Out of This World) and the issues experienced on real hardware are not present, though stability will vary depending on the game and which option you use. Just for comparison, that means the Max option is effectively 7.16 MHz. The latest standalone version of Snes9x and all of the libretro cores builds can overclock by reducing the number of emulated CPU/memory access cycles from 6, 8, and 12 to either 4, 5, and 6 (Compatible) or 3, 3, and 3 (Max) respectively. It also does not allow you to go over 250% clock speed, which isn't enough to fully get rid of slowdowns in some games. It is more stable than the real hardware while overclocked and won't exhibit the same issues, but it is still very unstable especially if you adjust the frequency multiple times. MAME SNES emulation is very demanding by default and activating the overclock only makes it worse. Only MAME has an option to change the main CPU frequency, which requires you to enable cheats. 7.6 MHz: Color palette errors sprites fail to render.6.6 MHz: Color palette errors sprites fail to render.4.1 MHz: Small amounts of sprite breakup occasionally very little slowdown.In testing overclocks on the original hardware, the following issues occur (speeds listed represent the maximum effective clock rate): In the case of ROM access, it also depends on whether bit 0 of CPU register 420D is set to 0 (SlowROM, 8) or 1 (FastROM, 6). 21.477/6 = 3.58) and memory access can take 6, 8, or 12, depending on the area of RAM is accessed. This is because any CPU operation takes 6 master cycles (i.e. Though uncommon, this is required for some games, a notable example being Contra Force.įor an NTSC SNES, the master clock rate is approximate ~21.477 MHz, but the CPU's effective clock rates are ~3.58 MHz, ~2.68 MHz, or ~1.79 MHz. ![]() If you happen to experience graphical glitching or crashes with a PPU overclock, try the VBlank Scanlines ("After NMI" in Mesen) option instead. ![]() 240 Post-render Scanlines (Referred to as "Before NMI" in Mesen) should be more than enough for most games. ![]() Both are found under Options > Emulation > Overclocking.įor PPU Overclocking, the number of additional scanlines is user-defined. Mesen as of 0.2.2 includes the same feature, as well as CPU overclocking. PuNES as of 0.101 includes the same feature. This method doesn't cause audio distortion. įCEUX as of 2.2.3 includes an overclocking option which works by adding additional scanlines to the PPU loop. Overclocking is possible on real hardware, but doing so also speeds up the audio unless you're using a special hardware mod like the HiDefNES which does allow for overclocking without changing the audio pitch.
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