Changes

|successor = [[ZX Spectrum emulatorsLine|ZX Spectrum]]

The '''[[wikipedia:ZX81|ZX81]]''' was a Z80-based home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporationreleased on March 5, 1981, and had a retail price of {{Inflation|USD|99.95| 1981}}. It had a Z80 at 3.25 MHz with 1KB of RAM.

! scope="col"|Operating SystemPlatform(s)

! scope="col"|[[libretro|Libretro Core]]! scope="col"|Relative Speed<ref group=N name=RelativeSpeed>As calculated by Carlo Delhez's clkfreq, originally distributed with his XTender emulator. The ZX81 has relatively complicated timing mechanics, depending on signalling of WAIT during NMI; relative speed is a measurement of how closely an emulator matches a real machine in terms of clock cycles spent processing within a frame. 100.0% denotes the same execution speed as a real machine.</ref>! scope="col"|<abbr title="Free/Libre and Open-Source Software">FLOSS</abbr>

! scope="col"|Relative Speed<ref group[[Recommended Emulators|Recommended]]|-! colspan=N name"8"|PC / x86|-| [[Clock Signal|CLK]]| align=RelativeSpeed>As calculated by Carlo Delhez's clkfreq, originally distributed with his XTender emulator. The ZX81 has relatively complicated timing mechanics, depending on signalling of WAIT during NMI; relative speed is a measurement of how closely an emulator matches a real machine in terms of clock cycles spent processing within a frameleft|{{Icon|Linux|macOS|FreeBSD}}| [https://github. com/TomHarte/CLK/releases {{clkVer}}]| {{✗}}| 100.0% denotes the same execution speed as a real machine| {{✓}}| {{✓}}| {{✓}}|-| [[ZEsarUX]]| align=left|{{Icon|Windows|Linux|macOS|FreeBSD}}| [https://github.<com/chernandezba/zesarux/ref>releases {{ZEsarUXVer}}]| {{✗}}| 110.9%| {{✓}}| {{✓}}| {{✓}}|-! scope="col"|[[Recommended EmulatorsEightyOne]]| align=left|{{Icon|Windows}}|Recommended][https://sourceforge.net/projects/eightyone-sinclair-emulator/files/ {{EightyOneVer}}]| {{✓}}| 114.3%| {{✓}}| {{✓}}| {{✓}}

|[[EightyOne]]Spud81| align=left|{{Icon|Windows}}|[https://sourceforge1drv.netms/projectsu/eightyone-sinclair-emulator/files/ 1s!Ar4VkKtk_3JzgQFkPzv4WgWTMHNc?e=trhIHh 0.12221]|{{✓✗}}| 114.9%|{{✓✗}}|114.3%{{✓}}|{{✓~}}

|[[ZEsarUX]https://sourceforge.net/projects/sz81/ SZ81]<br/><small>(xz80 & z81 based)</small>|Multi-platformalign=left|{{Icon|Windows|Linux|macOS|FreeBSD|AmigaOS}}|[httpshttp://githubsz81.sourceforge.comnet/chernandezba#downloads 2.1.7] <br/zesarux>[http:/releases 7/rullf2.xs4all.nl/sz81/ 2.3.110 (Unofficial)]|{{✗}}| 100.0%|{{✓}}|110.9%{{✗}}|{{✓~}}

|[[Clock Signal|CLKMAME]]| align=left|{{Icon|Windows|Linux|macOS and UNIXalikes|FreeBSD}}|[httpshttp://githubwww.commamedev.org/TomHarte/CLK/releases release.html {{clkverMAMEVer}}]|{{✗✓}}| Not tested|{{✓}}|100.0%{{✓}}|{{✗}}

|[httpshttp://sourceforgezxplanet.emuunlim.netcom/projects/sz81/ SZ81mme-review.htm MTMW] <br/><small>(xz80 & z81 basedaka 'MulTiMachine')</small>|UNIX, align=left|{{Icon|Windows, [[Amiga emulators|Amiga]]<br />Linux, macOS}}|[httphttps://sz81www.sourceforgezophar.net/#downloads 2sinclair/multi-machine.html 1.7] <br/>[http://rullf2.xs4all.nl/sz81/ 2.3.930b]|{{✗}}| Not tested|{{✗}}|100.0%{{✗}}|{{✗}}

|[[MAMENo$|No$ZX]]|Multi-platformalign=left|{{Icon|Windows|DOS}}|[http://wwwproblemkaputt.mamedevde/zx.org/releasehtm 2.html 0]| {{MAMEVer✗}}]| 100.1% <br/><ref group=N name=NoCashSpeed>After turning off the simulated hardware improvements that were not standard in the original computer.</ref>|{{✓✗}}|{{✓✗}}|Not tested|{{✗}}

|[[No$|No$ZX]http://zx81.vb81.free.fr VB81 XuR]| align=left|{{Icon|Windows, DOS}}|[http://problemkaputtzx81.devb81.free.fr/zxdownload/VB81_XuR_EXE.htm 2.0zip 16/04/2022]|{{✗}}| 100.5%|{{✗✓}}|100.1% <br/><ref group=N name=NoCashSpeed>After turning off the simulated hardware improvements that were not standard in the original computer.</ref>{{✓}}|{{~✗}}

|[http://zxplanetfreestuff.emuunlimgrok.com/mme-reviewco.htm MTMW] <bruk/><small>(aka 'MulTiMachine')<vb81/small>VB81]| align=left|{{Icon|Windows}}|[httpshttp://wwwzx81.zopharvb81.netfree.fr/vb81/sinclairdownload/multivb81-machinefull.html exe 1.30b30]|{{✗}}| Not tested|{{✗✓}}|Not tested{{✗}}|{{✗}}

|[http://zxplanet.emuunlim.com/xtender-review.htm XTender2]| align=left|{{Icon|DOS}}|[http://www.zx81.nl/ beta 13]|{{✗}}| Not tested|{{✗}}|Not tested{{✗}}|{{✗}}

|[http://www.retroisle.com/sinclair/zx81/emulators.php ZX81 Emulator] <br/><small>(Paul Robson)</small>| align=left|{{Icon|DOS}}|[http://www.zx81.nl/ 4.00]|{{✗}}| 101.5%|{{✗}}|Not tested{{✗}}|{{✗}}

! colspan="78"|Mobile/ ARM

|[https://sourceforge.net/projects/sz81/ SZ81] <br/><small>(xz80 & z81 based)</small>|[[wikipedia:Sharp align=left|{{Icon|Zaurus|Sharp Zaurus]], <br/>GPH GP2X/Dingoo|Wiz, <br/>Dingoo A320}}|[http://sz81.sourceforge.net/#downloads 2.1.7]|{{✗}}| 100.0%|{{✗✓}}|100.0%{{✗}}|{{✗}}

|[https://zx81-ios.weebly.com ZX81 iOS]|[[wikipedia:IOSalign=left|{{Icon|iOS]], <br/>Devices with METAL framework support }}|[https://itunes.apple.com/us/app/zx81/id1180117434?mt=8 1.511.1]|{{✗}}|{{✓}}|100.61% <br/><ref group=N name=ZX81iOSSpeed>Provided by Kevin Palser the developer (and author of this note) because the app cannot load external programs, such as Carlo Delhez's clkfreq, due to Apple developer restrictions for iOS. Permission to include clkfreq in the app cannot be granted because Dr Delhez sadly passed away in 2015.</ref>| ?| {{✓}}|{{~}} <br/><ref group=N name=ZX81iOSNeutered>This app is neutered as loading of external programs into emulator apps from the App Store is prohibited by Apple. However, it does have a growing selection of programs included with permission granted by their authors.</ref>