Just a thought. The OS4 68K emulation is JIT based. I'd expect, therefore that 68K code runs at speeds not far short of native.
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Native as in PPC code, I meant
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For many IO device drivers, wouldn't the emulated 68K code already be faster than the hardware could keep up with anyway? I'd imagine stuff like graphics hardware drivers and the like would benefit most from 100% PPC native code.
Still a 100% PPC native OS should be the overall goal ;-)