BIOS Y2K Bugfix

Year2000 (ver 2.16) - Abandonware

Turbo Pascal "error200" Bugfix

TPPATCH (ver unknown) - Abandoned Freeware

Antivirus

F-Prot Anti-Virus for DOS (ver 3.16f) - Abandonware


Library replacements

Program A/V driver replacements (ver various) - Abandoned Freeware

Legal Copy Protection workarounds

Program code JMP mods (ver various) - Abandonware


System Speed Fixes

Note: Faster processors require more radical approaches to slowing, but beware that some slowdowns can affect audio and system response.
Video bus speed and especially video cache reduction are two often overlooked, but very effective ways to slowdown for games.
Often you will have to run multiple utilities to achieve your goal, and probably need custom setups for each game.

System Speed Test (ver 6.00) - Abandonware


CPUSPEED (ver 2.1) - Freeware

Throttle (ver 14-Nov-2021) - Freeware

SetMul (ver 1.24) - Freeware
~ CWSDPMI (ver 7)

~ [CSDPMI7B .zip]

SMB (ver 2.09) - Freeware
~ CWSDPMI (ver 7)

~ [CSDPMI7B .zip]

NVClock (ver 0.8 beta 4) - Abandoned Freeware
~ CWSDPMI (ver 7)

~ [CSDPMI7B .zip]

CPUCACHE (ver 1.00) - Abandoned Freeware
~ includes: SLOWDOWN (ver 3.10) TSR

slowDOS (ver 1.03) - Freeware TSR

DMASLO (ver 12/10/88) - Abandoned Freeware TSR

AT-SLOW (ver 4.10) - Shareware made Abandoned Freeware TSR