Hey check this out https://www.youtube.com/watch?v=DJC2EB-za3s
I have my setup solely for PSX and struggled with it on the B+. The Pi 2 however runs every PSX game I have tried flawlessly. Sound and speed wise.
Currentally I am 22 15 hours into Final Fantasy Tatics, blitzed through Diablo for a few hours and just finished Legacy of Kain – Soul Reaver. I have played about an hour into ff9 with no issues with any of the above.
I cannot comment on N64 as I have not tried.