Yes, like I said before, the Gamecube has only 24MB of RAM. It does just fine loading little pieces of the game at a time off the optical drive, which, as Allnatural said, is far slower than any modern hard drive. If a hard drive were not fast enough, then the optical drive on a real Gamecube would be in even worser straights. The CPU is by far the greatest bottleneck in Gamecube emulation, so if you overclock to maybe 20GHz, you might get up to full speed. (I don't think that speed has been achieved even on liquid nitrogen cooling though, so in other words, no full speed Gamecube emulation for now, except for a few games like Bust-a-Move 3000.)