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Comment by oppositelock | Hacker News Reader

The original PowerPC on Intel Rosetta was pretty amazing.

First, most programs do much of their work inside the OS - rendering, network, interaction, whatever, so that's not emulated, Rosetta just calls the native OS functions after doing whatever input translation is necessary. So, nothing below a certain set of API's is translated.

You have to keep a separate translated binary in memory, and be able to compile missing bits as you encounter them, while remembering all your offset adjustments. It worked amazingly well during the PowerPC transition. Due to so many things running natively on x86, the translated apps frequently faster than running native on PowerPC macs!

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> the translated apps frequently faster than running native on PowerPC macs!

This gets repeated a lot and it's generally false. In fact, most of the time they were slower, and realistically you would expect this. On a clock for clock basis, an OG Mac Pro 2.66GHz was about 10-20% slower than a Quad G5 2.5GHz running the same PowerPC software. In some benchmarks, the Quad G5 was still faster at running PowerPC software than the 3.0GHz (see https://barefeats.com/quad06.html ). When the Core Duo had to pay the Rosetta tax, even upper-spec G4s could get past it (https://barefeats.com/rosetta.html) and it stood no chance against the G5.

Where I think this misconception comes from is that on native apps (and Universal apps have native code), these first Intel Macs cleaned the floor with the G4 and most of the time nudged past even the mighty Quad, and by the second generation it wasn't a contest anymore. But for the existing PowerPC software that was available during the early part of the Intel transition, Power Macs still ran PowerPC software best overall. It wasn't Rosetta that made the Intel Macs powerful, it was just bridging things long enough to buy time for Universal apps to emerge. Rosetta/QuickTransit was marvelous technology, but it wasn't that marvelous.

History repeats itself. Even though Apple didn’t make the claim this time, they did claim that PPCs would run 68K apps faster because they would spin much of their time running native code. This wasn’t true then either - at least not for the first gen PPC Macs.

I had a quad 2.5GHz water cooled Mac Pro on my desk, and the OG Intel mac pro, as well as Apple's dev system. I can tell you with 100% certainty, that Google Earth ran faster on the Intel Mac Pro under Rosetta than natively on the PPC Mac Pro, as I'm the person who ported it. When I had the native version working on Intel, that was the fastest of all, by far.

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