for DC Demul is better, no idea how win 2 will handle.
For Saturn, if win2 support mednafen Saturn Retroarch core is better than SSF. SSF is still fine though.
For PSX I prefer mednafem-Beetle PSX in terms of acuuracy, but is demanding
Kega is no longer the most accurate for MD. Gensis plus GX core is better, or Exodus.