It thin that @Aremis may be confusing the “Compiled for x86” with the fat binaries that included PPC and x86 code branches.
There was that three year transition where the fat binaries came out and mostly all was well. The older PPC systems eventually had issues because they did not have the horse power that the G5s had and the PPC branches started becoming less optimized (Apple aint got no more time for that). The late G4s were okay because they had high clock speeds and Altivec was utilized to the max.
By the time that they phased out support for the non-G5 and x86 architectures, they had been encouraging their developers to develop for x86 because they wanted to get rid of the fat binaries. As a result a lot of code would run on the G5s but was not optimized, and they were also running on the fly instruction translation/emulation because the G5s could handle it; it had 64bit registers used to run the x86 code in 32 bit mode. As a result, if you still managed to get a non support version of OSX on your G4 or older hardware, it was balls slow. Stripping out the x86 from the fat binary forced the PPC path which was not bad. Think of this like the current " Your battery is to weak to run the new iOS are acceptable speeds" deal. Some people on the the not so distant iPhones don’t have the issue when they by-pass this feature while others have phones that power off because they cannot handle the load (unless they have new batteries of course slight_smile:
There was coverage of this in LKML for a while as Icculus and a few others were championing a fat binary to deal with the Linux x86/x86_64 debacle. they were citing Apple’s model as poster child while also point out some of the flaws in the Apple approach. Icculus had a working patch for the Linux kernel that would work on day one.