The emulation shouldn’t be a lot of a problem for these days emulation can be done by using JIT’s or AOT’s. Basicly by either converting the opcodes of one executable to be compatible with another architecture or to either do that at runtime. Both will most certainly cause a drop in speed but it wont be that much of a drop as compiling for x86 generic instead of for instane amd athlon.

But I heard that they are to release normal MacOSX and I-MacOSX. I-Mac would be the one with Intel executables. So code size wouldn’t be an issue except for third parties wanting to deliver their product in one download/disk/etc instead of multiple.

The intel processors will not support the old instructions, and as such there won’t be any optimizing for common opcodes, or optimizing for it or whatnot. PowerPC instructions that need to be executed will execute on a simulated G3, and will do so at a much slower speed that native execution.

i.e. Recompiled software will probably run faster (assuming the intel chips are faster, which they basically are), and some software will run really slow because it uses emulation.

Code size remains an issue, but disks are so large, and data so much more of a bit-consumer, that I don’t think the increased executable size will really matter at all.