Sega Saturn Not so much a big PC in today's standards.
Not accurate... the Saturn is a complex system with multiple CPUs. It's a very difficult emulation to write nevermind have the processing power to pull it all off. It's possible the average desktop PC isn't beefy enough to pull that off yet. We're talking about two CPUs, two video chips, two sound chips... they really maxed out the hardware potential of that system. In fact that's why the great Saturn games took so long. The learning curve for that unique platform was
way too steep even for Sega's developers.
Once you get up to N64 you're talking emulating a 64 bit CPU (running on a 32 bit bus) within a 32 bit emulation system... you hit a wall
really fast in terms of what is possible there without some really fancy coding footwork that won't be necessary if people just wait for the next level of hardware to come around.