I think it's just barely possible for the fastest NES and GB emulators to use this trick for one single frame of lag reduction. Here, you have eight inputs (as

I think it's just barely possible for the fastest NES and GB emulators to use this trick for one single frame of lag reduction. Here, you have eight inputs (assumes one player on the NES.) But there's a trick: up+down and left+right aren't physically possible due to a rocker in the D-pad. So as a whole, there are nine possible D-pad states instead of sixteen. With four buttons, that's sixteen possible states. So the total is 144 states. Now look at QuickNES, blargg's masterpiece NES emulator that runs fullspeed on a 66MHz PowerPC system. If you had the fastest, overclocked octacore CPU Intel makes, you may be able to pull off 144 instances of the emulation. Especially since you don't have to actually output the audio and video for all the missed predictions to the real hardware. Or perhaps more sanely ... most games don't have you using start+select while playing. I think people would be willing to accept a large jitter when pressing those two buttons. So now you're talking 36 instances, which starts to look very reasonable. At least, for emulators that are okay with sacrificing accuracy. The most popular NES emulators today require 800MHz (Nestopia), 1.6GHz (Nintendulator), and I'm not sure on puNES, but presumably just as high. 36 instances of those are unlikely. Still, this would be a fun experiment if anyone were willing! :D Of course, the end result is a 16ms lag reduction. And again, I need to stress ... I get that latency stacks, but ... you're really going to have a hard time even telling the difference between the two. Even if you're one of those people who can beat Dodonpachi or Ninja Gaiden or Battletoads on one life.