We actually had an Intel build of most of OSX from the beginning. Various parts would go stale and then a motivated engineer would dive in and get it running again on some specific set of audio and video hardware. At some point the existence of the "Marklar" project leaked out, but several of us at Apple had various builds running on commodity PC hardware.

> I remember this fiasco. And then shortly after that, rumors started popping up that Apple was working on porting OSX to x86.

Article concerns the last half of 1999. It turns out Mac OS X development on PPC was shadowed on Intel (after all, since 1995 NeXTSTEP ran on Intel), but the rumor didn't appear until nearly 3 years later in Spring 2002, and it didn't really have any traction and quickly subsided long before Jobs' announcement confirming the rumor another 3 years after that in Summer 2005.[1] No one still expected it by then, but at the same time, no one was all that surprised. Business as usual that Apple kept a secret for 3 years, but it's pretty crazy how they somehow suppressed a true rumor for 3 years after it was published.

[1] https://en.wikipedia.org/wiki/MacOS#PowerPC–Intel_transition

Apple really did have to push the (Motorola) G4 way more than they'd have liked. A 1999 G4 was a 400MHz G4 on a 100MHz FSB. By the 2003, when they were done with Motorola and and onto the IBM G5, they were running a pair of 1.25GHz G4's on a 167MHz FSB...

I'm sure it was possible to get a lot of speed out of workloads that ran out of the on-chip cache, but I'm equally sure that it was easy to wind up constrained by memory bus bandwidth. I tried to convince myself to buy one and switch to OS X, but couldn't get past the architectural limitations. (Which were worse because I'd also have wanted to run Windows under emulation.)