Changes

Overclocking is the process by which the CPU clockspeed clock speed is increased. The reason for doing this would be to reduce slowdown in games, or to increase the framerateframe rate. However, as this is a hack and not intended by designers, it can result in many issues. Certain systems can have an overclocked CPU with few if any issues, while others can not overclock without major issues.

{| class="wikitable" style="text-align:center;"

! scope="col" style="text-align: center;"|System! scope="col" style="text-align: center;"|Normal clock! scope="col" style="text-align: center;"|Hardware Overclock! scope="col" style="text-align: center;"|Emulation Overclock! scope="col" style="text-align: center;"|Overclock levels

| style="text-align: center;"|[[Nintendo Entertainment System emulators|NES]]| style="text-align: center;"|1.79 MHz| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|No{{✓}}| style="text-align: center;"|?

| style="text-align: center;"|[[Super Nintendo emulators|SNES]] (Main CPU)| style="text-align: center;"|3.58 MHz| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|No{{✓}}| style="text-align: center;"|4.1 -7.6 Mhz

| style="text-align: center;"|[[Super Nintendo emulators|SNES]] SFX1(Super FX 1)| style="text-align: center;"|10.5 MHz| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|40-60 Mhz

| style="text-align: center;"|[[Super Nintendo emulators|SNES]] SFX2(Super FX 2)| style="text-align: center;"|21 MHz| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|40-60 Mhz,

| style="text-align: center;"|[[Mega DriveSega Genesis emulators|Sega Genesis]]| style="text-align: center;"|7.7 MHz| style="text-align: center;"|Yes{{✓}}<ref name="kyorune">http://kyorune.com/modding/article.php?id=73</ref>| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|13.1-25.4 MHz<ref name="kyorune"/>

| style="text-align: center;"|[[PlayStation emulators|PlayStation]]| style="text-align: center;"|33.8 MHz| style="text-align: center;"|Yes{{✓}}<ref name="kraut">https://www.youtube.com/watch?v=HapnSOseDfw</ref>| style="text-align: center;"|No{{✓}}| style="text-align: center;"|66Mhz<ref name="kraut"/>

| style="text-align: center;"|[[Sega Saturn emulators|Sega Saturn]]| style="text-align: center;"|28.6 MHz*| style="text-align: center;"|No{{✗}}| style="text-align: center;"|No| style="text-align: center;"|-{{✗}}

| style[[Nintendo 64 emulators|Nintendo 64]]|93.75 MHz|{{✓}}<ref name="textn64oc">http://www.gamesx.com/misctech/n64oc.htm</ref>|{{✓}}|125-align: center;187.5 Mhz<ref name="n64oc"/>|-|[[Neo Geo emulators|Neo Geo]]| style="text-align: center;"|12 MHz| style="text-align: center;"|Yes{{✓}}<ref name="neooc">http://www.neo-geo.com/forums/showthread.php?158016-68K-s-guide-to-overclocking-your-Neo-Geo-AES</ref>| style="text-align: center;"|Yes{{✓}}| style="text-align: center;"|14-18 MHz<ref name="neooc"/>|-|[[3DO emulators|3DO]]|12.5 MHz|{{na|text=Unknown}}|{{✓}}|{{na}}

<nowiki>*</nowiki>Sega Saturn has two SH-2 CPUs ==MAME==By default [[MAME]] allows you to change the clock speed of the systems it emulates (including consoles) to anything between 50% to 250% of the original clock speed, the only requirement is that you enable cheats for that game/system. ==NES==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<ref name="HiDefNESoverclock">https://youtu.be/QnQuBN3iYVA?t=4m8s</ref>.

==Famicom (NES)==[[FCEUX]] as of 2.2.3 includes an overclocking option which works by adding additional scanlines to the PPU loop. This method doesn't cause audio distortion. It is found under Config > Timing. [[puNES]] as of 0.101 includes the same feature. It is found under Tools > PPU Hacks. [[Mesen]] as of 0.2.2 includes the same feature, as well as CPU overclocking. Both are found under Options > Emulation > Overclocking. For PPU Overclocking , the number of additional scanlines is possible on real hardwareuser-defined. 240 Post-render Scanlines (Referred to as "Before NMI" in Mesen) should be more than enough for most games. If you happen to experience graphical glitching or crashes with a PPU overclock, but no emulator allows try the VBlank Scanlines ("After NMI" in Mesen) option instead. Though uncommon, this is required for itsome games, a notable example being Contra Force.

The main For an NTSC SNES , the master clock rate is approximate ~21.477 MHz, but the CPU ran at 's effective clock rates are ~3.58 MHz , ~2.68 MHz, or ~1.79 MHz. This is because any CPU operation takes 6 master cycles (i.e. 21.477/6 = 3.58) and memory access can be overclockedtake 6, 8, or 12, depending on the area of RAM is accessed. However In the case of ROM access, it causes issuesalso depends on whether bit 0 of CPU register 420D is set to 0 (SlowROM, 8) or 1 (FastROM, 6). With those who have tested it, the following issues occur<ref name="Fullsnes - No$SNS Specs">http: //problemkaputt.de/fullsnes.htm#cpuclockcycles</ref>

*"4.1 MHzIn testing overclocks on the original hardware, the following issues occur (speeds listed represent the maximum effective clock rate): Small amounts of sprite breakup occasionally; very little slowdown.

* 4.1 MHz: Small amounts of sprite breakup occasionally; very little slowdown.*5.1 MHz: Sprite breakup; no slowdown* 6.6 MHz: Color palette errors; sprites fail to render* 7.6 MHz: Color palette errors; sprites fail to render. Freezes after a few minutes.<ref name="SNES overclock">http://web.archive.org/web/20070629163744/http://www.undergroundcm.com/index.php?option=com_content&task=view&id=15&Itemid=38</ref>

*6Only MAME has an option to change the main CPU frequency, which requires you to enable cheats. MAME SNES emulation is very demanding by default and activating the overclock only makes it worse. 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.6 MHz: Color palette errors; sprites fail It also does not allow you to rendergo over 250% clock speed, which isn't enough to fully get rid of slowdowns in some games.

*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. Just for comparison, that means the Max option is effectively 7.6 16 MHz: Color palette errors; sprites fail to render. Freezes after Gameplay is not sped up (assuming the game is not in a few minutesconstant 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."<ref name="SNES overclock">http://web.archive.org/web/20070629163744/http://www.undergroundcm.com/index.php?Also to note, some games may work better with the Max option=com_content&task=view&id=15&Itemid=38</ref> There are no SNES emulators that allow rather than Compatible, as appears to be the case for an overclocking Mega Man X1 which has a bit of graphical corruption under very specific conditions when using the Compatible option, likely because of those so try both if you encounter issues.  ===SFX chip===

The SFX chip however can be overclocked with fewer issues on real hardware or emulationwith fewer issues than overclocking the CPU. It does however However, tests have shown that overclocking can increase the speed of the game as well, in addition to increasing the frame rate and removing slowdown.<ref name="Dragon50hztest">https://www.youtube. com/watch?v=tfNI3HpUt-4</ref>

Tests have shown that overclocking can increase the speed of the game, in addition to increasing the framerate and removing slodown.<ref name="Dragon50hztest">https://www.youtube.com/watch?v=tfNI3HpUt-4</ref> {| class="wikitable" style="text-align:center;"

! scope="col" style="text-align: center;"|Clock speed! scope="col" style="text-align: center;"|Time! scope="col" style="text-align: center;"|Increase

| style="text-align: center;"|Normal| style="text-align: center;"|1'46'02| style="text-align: center&mdash;"|-------

| style="text-align: center;"|50hz50Hz| style="text-align: center;"|1'23'78| style="text-align: center;"|27.711%<ref name="Dragon50hztest"/> 

The latest standalone version of [[Snes9x]], as well as [[RetroArch|Snes9x-Next]] allows for SFX overclocking, as well as and [[higan|bsnes-mercury]], though allows for SFX overclocking. Though in the latter the increase in CPU requirements can be noticeable.

Overclocking the The main CPU can be overclocked on real hardware but will also has the effect of speeding speed up the audio as well.<ref>When you overclock http://nfggames.com/games/pce/</ref> [[Mednafen]] allows overclocking the CPUup to 100x, the without affecting audio speeds up as wellpitch, in its non-default [{{MednafenURL|documentation/pce_fast.<html}} pce_fast] core via the [{{MednafenURL|documentation/ref>pce_fast.html#pce_fast.ocmultiplier pce_fast.ocmultiplier}}] setting.

Some emulators like the [[libretro]] port of [[Mupen64Plus]] - have an overclocking option called "VI Refresh", and [[1964]] UltraFast (a very old fork of 1964) have an option to overclock the CPU. Some games (see the list below) can take advantage of overclocking and improves frame rate, while most others (such as Super Mario 64) have built-in frame rate limiter and unaffected by overclocking.<ref>http://forum.pj64-emu.com/showpost.php?p=51810&postcount=6</ref><ref>http://www.emucr.com/2011/02/1964-ultrafast-v3.html</ref> ===List of games that can take advantage of overclocking===* ''A Bug's Life''* ''Aidyn Chronicles - The First Mage''* ''Armorines - Project S.W.A.R.M.''* ''Big Mountain 2000''* ''Carmageddon''* ''Conker's Bad Fur Day''* ''Destruction Derby 64''* ''Disney's Donald Duck - Goin' Quackers / Donald Duck - Quack Attack''* ''Duck Dodgers Starring Daffy Duck / Looney Toons - Duck Dodgers''* ''Earthworm Jim 3D''* ''Extreme-G''* ''Extreme-G XG2''* ''F1 Racing Championship''* ''F-1 Pole Position 64''* ''Gex 3 - Deep Cover Gecko''* ''GoldenEye 007''* ''Hot Wheels Turbo Racing''* ''Human Grand Prix - New Generation''* ''Jet Force Gemini / Star Twins''* ''Jeremy McGrath Supercross 2000''* ''Kobe Bryant's NBA Courtside''* ''Madden Football 64''* ''Madden NFL 99-2002''* ''Mario Kart 64 (Multiplayer and some tracks only)''* ''Milo's Astro Lanes''* ''Monaco Grand Prix - Racing Simulation 2''* ''Monster Truck Madness 64''* ''NASCAR 99/2000''* ''NBA In the Zone 98 / NBA Pro 98''* ''Off Road Challenge''* ''Perfect Dark''* ''Quake II''* ''Racing Simulation 2''* ''Rakuga Kids''* ''Rayman 2 - The Great Escape''* ''Roadsters Trophy''* ''San Francisco Rush - Extreme Racing (Multiplayer only)''* ''San Francisco Rush 2049 (Multiplayer only)''* ''South Park Rally''* ''StarCraft 64''* ''Starshot - Space Circus Fever''* ''Super Robot Spirits''* ''Taz Express''* ''The New Tetris''* ''Tom Clancy's Rainbow Six''* ''Tonic Trouble''* ''Toy Story 2''* ''Transformers - Beast Wars Transmetal''* ''Turok 2 - Seeds of Evil / Violence Killer - Turok New Generation''* ''V-Rally Edition 99''* ''WCW vs. nWo - World Tour''* ''World Cup 98''

Recent builds of [[Dolphin]] support supports overclocking and underclocking the CPU. Overclocking can remove slowdown from games that have them, pushing them closer to their actual locked frameratetarget frame rate. It causes several issues with many games, so don't expect it to be a perfect solution. Dolphin used to have a VBeam Speed Hack that doubled GPU clock rate. This has since been removed, as the developers found that it didn't really help in many cases.

Dolphin ==PlayStation==On real hardware, overclocking is possible using [http://djky2k3.tripod.com/psx_oc.html this modification]. On emulators, [https://github.com/SonofUgly/PCSX-Reloaded/releases this modified build] of [[PCSX-Reloaded|PCSX-R]] as well as [http://ngemu.com/threads/pcsxr-pgxp.186369/ this fork] allow for overclocking, though most games will break past 1.5x clock speed. Recent builds of Beetle PSX (the libretro fork of Mednafen's PS1 core) also has a VBeam Speed Hack that doubles GPU support overclocking, by way of removing timing penalties instead of increasing clock ratespeed. The developers don't prefer EPSXe also natively supports overclocking up to 4x. Hydro Thunder benefits a lot from it be used, and it and can currently only be enabled on running at a per-game basisconstant 30 FPS without any other issues.

On fat older PS2's original model PS2s, you can overclock by a small amount without too much problem, but the biggest issue will be sped -up audio. Slim model PS2's PS2s use the GPU's clockrate clock rate as a base for the CPU (multiplying the GPU's clock by 2), so overclocking the CPU will also overclock the GPU resulting in many visual problems.<ref name="PS2OC">http://nfggames.com/forum2/index.php?topic=2220.0</ref>

All recent builds of [[PCSX2 uses ]] have a speed hack that allows you to increase the EE cycle-rate without having any effect on the CPU clock as audio, although it does still break a few games most of them run fine and with less slowdown. The emulator also has a basespeed hack called VU Cycle Stealing, and divides which allows for increased GPU clockrateperformance at the cost of CPU cycles. It gives an incorrect FPS readout, so overclocking will result in visual problems too, as well as sped up audio. [http://www.mediafire.com/download/u204iktybl9z2t4/Pcsx2_OCthough.rar PCSX2 OC Builds]

==PSP==[[PCSX2PPSSPP]] Also has a speed hack called VU Cycle Stealing, which allows for increased GPU performance at over/underclocking of the main CPU. Due to Sony underclocking the cost of CPU cyclesto 222 MHz then removing the underclock in a later firmware update to allow it to run at 333 MHz<ref>https://en. It does give incorrect FPS readoutwikipedia.org/wiki/PlayStation_Portable_hardware#Technical_specifications</ref> (and thus not having games closely tied to clock rate), overclocking the system (and emulating an overclocked system) results to next to no ill effects.

Final burn alpha [[FinalBurn Alpha]] allows for overclocking of Neo Geo games. MAMEUIFX (aka MAME32FX) also allows for overclocking.<ref>http://mame32fx.altervista.org/home.htm</ref> All Neo Geo should run at full speed when overclocked.

==Mega DriveSega Genesis==The original hardware can be overclocked leading to faster/smoother gameplay. <ref>http://www.youtube.com/watch?v=SVrElANZg2M</ref>

Most Genesis emulators don't allow overclocking. The [[Genesis Plus GX]] dev developer, for instance, says that implementing overclocking is "not easy to add without potentially break other things. "<ref>https://code.google.com/p/genplus-gx/issues/detail?id=223</ref>

The [http://aamirm.hacking-cult.org/www/regen.html Regen emulator ] allows overclocking in the dev build version.<ref>http://segaretro.org/Regen</ref> Games with sprite flicker, like Altered Beast, and games with some slowdown, like Rambo III or Mega Man: The Wily Wars, play perfectly with Regen's "Overclock M68000" setting at 732 (1.5x original speed). The game speed and audio are unaffected by overclocking. BlastEm and HazeMD also allow for overclocking but neither are really recommended for normal usage. ==3DO==[[Phoenix (emulator)|Phoenix]] and standalone Windows version of [[4DO]] allows up to 4.0/400% of the original 3DO clock speed, making some low frame rate titles such as [[wikipedia:Doctor_Hauzer|Doctor Hauzer]] and [[wikipedia:Killing_Time_(video_game)|Killing Time]] more playable. Also possible to overclock CPU in [[libretro]] version of [[4DO]]<ref>https://docs.libretro.com/library/opera/#core-options</ref> in options in core's quick menu after game launch, but only to 2.0x speed, that still may seem slow. The possibility of this function to break games (like incorrect physic and unplayable speed) is unknown.