It will be slower, but I don't think unusable. Actually, comparing gameboy (and other consoles) is not really a good idea, as they are systems where getting all

It will be slower, but I don't think unusable. Actually, comparing gameboy (and other consoles) is not really a good idea, as they are systems where getting all the processors exactly in sync is important and difficult. Emulating a PC is much easier, as no-one expects to get exactly equal speeds out of processors, as every PC model is slightly different. As I say, I (and many other people) emulated x86 windows on PPCs for years. I ran visual studio and it dragged a little, but was fairly usable. Certainly it won't be as fast, but then again by the time x86 has died and people have moved, hopefully systems will have got fast enough to make up the difference!