Changes

|{{✗}} ||{{✗}} ||{{✗}} ||{{✓}}|-|[[4DO|4DO / Opera]]|align=left|{{Icon|Windows}}<br>{{Icon|Linux|macOS|FreeBSD}}<small><ref group=N name=libretro>''Only available outside of Windows as a libretro core (e.g. [[RetroArch]]).''</ref></small>|[https://sourceforge.net/projects/fourdo/ 1.3.2.4]<br />[https://github.com/libretro/4do-libretro Git]|{{✓}} ||{{✓}} ||{{~}} <small><ref group=N name=active>''Main branch is dead, but the libretro core is still alive.</ref></small> ||{{✓}}

;[[4DO|4DO / Opera]]:A 4DO is a fork of the FreeDO emulation project, but the standalone version and is only available for Windows. The website has been shut down and the most recent release is a many years old<ref name="4DOSite">http://web.archive.org/web/20161213021202/http://www.fourdo.com</ref>. It can [[Overclocking|overclock]] up to 400% of the original 3DO clock speed, which makes low frame rate titles (e.g. [[wikipedia:Doctor_Hauzer|Doctor Hauzer]]) much more playable. It allows upscaling the game in a higher internal resolution by up to 2x, but the game is still only rendered at 480p. Severe audio glitches are very common no matter what settings are used. A libretro port renamed to Opera is also available, though overclocking options present only to 2.0x speed (unlike original 4.0x), that still may seem slow<ref>https://docs.libretro.com/library/opera/#core-options</ref>.