Editing Overclocking

Overclocking is the process by which the CPU clock speed is increased. The reason for doing this would be to reduce slowdown in games or to increase the frame 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"|System

! scope="col"|Normal clock

! scope="col"|Hardware Overclock

! scope="col"|Emulation Overclock

! scope="col"|Overclock levels

|[[Nintendo Entertainment System emulators|NES]]

|1.79 MHz

|{{✓}}

|{{✓}}

|{{na}}

|[[Super Nintendo emulators|SNES]] (Main CPU)

|3.58 MHz

|{{✓}}

|{{✓}}

|4.1-7.6 Mhz

|[[Super Nintendo emulators|SNES]] (Super FX 1)

|10.5 MHz

|{{✓}}

|{{✓}}

|40-60 Mhz

|[[Super Nintendo emulators|SNES]] (Super FX 2)

|21 MHz

|{{✓}}

|{{✓}}

|40-60 Mhz

|[[Sega Genesis emulators|Sega Genesis]]

|7.7 MHz

|{{✓}}<ref name="kyorune">http://kyorune.com/modding/article.php?id=73</ref>

|{{✓}}

|13.1-25.4 MHz<ref name="kyorune"/>

|[[Sega Dreamcast emulators|Sega Dreamcast]] (SH4 CPU)

|200 MHz

|{{✓}}

|{{✓}}

|220MHZ-240MHz

|[[PlayStation emulators|PlayStation]]

|33.8 MHz

|{{✓}}<ref name="kraut">https://www.youtube.com/watch?v=HapnSOseDfw</ref>

|{{✓}}

|66Mhz<ref name="kraut"/>

|[[Sega Saturn emulators|Sega Saturn]]

|28.6 MHz*

|{{✗}}

|{{✗}}

|{{✗}}

|[[Nintendo 64 emulators|Nintendo 64]]

|{{✓}}<ref name="n64oc">http://www.gamesx.com/misctech/n64oc.htm</ref>

|125-187.5 Mhz<ref name="n64oc"/>

|[[Neo Geo emulators|Neo Geo]]

|12 MHz

|{{✓}}<ref name="neooc">http://www.neo-geo.com/forums/showthread.php?158016-68K-s-guide-to-overclocking-your-Neo-Geo-AES</ref>

|{{✓}}

|14-18 MHz<ref name="neooc"/>

<nowiki>*</nowiki> Sega Saturn has two SH-2 CPUs

 

[[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 user-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, try the VBlank Scanlines ("After NMI" in Mesen) option instead. Though uncommon, this is required for some games, a notable example being Contra Force.

For 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. This is because any CPU operation takes 6 master cycles (i.e. 21.477/6 = 3.58) and memory access can take 6, 8, or 12, depending on the area of RAM is accessed. 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).<ref name="Fullsnes - No$SNS Specs">http://problemkaputt.de/fullsnes.htm#cpuclockcycles</ref>

In testing overclocks on the original hardware, the following issues occur (speeds listed represent the maximum effective clock rate):

* 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>

Only 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. 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.

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

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

! scope="col"|Clock speed

! scope="col"|Time

! scope="col"|Increase

|Normal

|1'46'02

|&mdash;

|50Hz

|1'23'78

|27.711%<ref name="Dragon50hztest"/>

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

The main CPU can be overclocked on real hardware but will also speed up audio.<ref>http://nfggames.com/games/pce/</ref>

[[Mednafen]] allows overclocking the CPU up to 100x, without affecting audio pitch, in its non-default [{{MednafenURL|documentation/pce_fast.html}} pce_fast] core via the [{{MednafenURL|documentation/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>

* ''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''

* ''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''

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.

On emulators, [[Duckstation]] allows you to overclock the CPU up to 1000% or 10x and also supports CD speed up and seek speed up. [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 support overclocking, by way of removing timing penalties instead of increasing clock speed. EPSXe also natively supports overclocking up to 4x. Hydro Thunder benefits a lot from it, running at a constant 30 FPS without any other issues.

On 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 PS2s use the GPU's 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]] have a speed hack that allows you to increase the EE cycle-rate without having any effect on the audio, although it does still break a few games most of them run fine and with less slowdown. The emulator also has a speed hack called VU Cycle Stealing, which allows for increased GPU performance at the cost of CPU cycles. It gives an incorrect FPS readout, though.

[[PPSSPP]] allows over/underclocking of the main CPU. Due to Sony underclocking the CPU to 222 MHz then removing the underclock in a later firmware update to allow it to run at 333 MHz<ref>https://en.wikipedia.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.

 

[[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.

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]] 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>

[http://aamirm.hacking-cult.org/www/regen.html Regen] 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.

 

 

Its SH-4 CPU can be overclocked from [https://www.retrorgb.com/easier-dreamcast-overclock-mod.html 200] to either 220 MHz (which is safer) or [https://www.racketboy.com/retro/overclock-your-dreamcast 240 MHz] (which isn't recommended). Some games which may struggle the original console in heavier scenes (like Soldier of Fortune) or don't run at full speed (like Sega Rally which runs at 55 vblanks/sec instead of 60) will work smoother. [[Flycast]] supports overclocking, and Sega Rally runs at full 60 vblanks/sec in [[Redream]].

[[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 [[Opera]]<ref>https://docs.libretro.com/library/opera/#core-options</ref>, a [[libretro]] fork of 4DO,<br> in options in core's quick menu after game launch, up to 4.0/50.00Mhz

 

The possibility of this function to break games (like incorrect physic and unplayable speed) is unknown.

 

 

In DSi and 3DS systems, it is possible to run classic DS games at higher clocks by the use of [[nds-bootstrap]]. This hypervisor has the option of running classic DS games in DSi mode, effectively overclocking the CPU from 67MHz to 133MHz. This change can remove slowdowns and improve framerate in some games, but can add instability in several others.

 

On real hardware some people changing xbox cpu with tualatin pentium III and upgrading RAM to 128mb (just like [[Development Kits]]) for [https://youtu.be/c66hfqw4SKc?t=456 low frame rate games like Half-Life 2].