Wow, I've been away wayyy to long. Forgive me bumping an older thread. 
That site actually belongs to me and yes, the hack is quite real and does work. The particular system mentioned is still in use right now, though with a 1GHz Sonnet G4 card instead of the G3.
The practical applications for the 66MHz hack, however, are extremely limited, especially since there's maybe a dozen useful PCI cards that are both compatible with old PowerMacs and a 66MHz bus. Not to mention the fact Radeons seem to hate sharing at 66MHz. The old memory bus remains a serious bottleneck too, You get around 10%-20% improvement with simpler everyday stuff and a decent boost in GPU-heavy gaming but not a lot else. Turning on Quartz Extreme with the faster PCI does boost video playback considerably.
If your PowerMac is already getting too slow for your needs this won't fix very much in long-term. It was part of a personal challenge to see how far these old systems could be pushed. I considered the project officially "done" about half a year ago since there's not much left to do unless we get better CPU upgrades or PCI graphics cards (very unlikely in both cases).
That site actually belongs to me and yes, the hack is quite real and does work. The particular system mentioned is still in use right now, though with a 1GHz Sonnet G4 card instead of the G3.
The practical applications for the 66MHz hack, however, are extremely limited, especially since there's maybe a dozen useful PCI cards that are both compatible with old PowerMacs and a 66MHz bus. Not to mention the fact Radeons seem to hate sharing at 66MHz. The old memory bus remains a serious bottleneck too, You get around 10%-20% improvement with simpler everyday stuff and a decent boost in GPU-heavy gaming but not a lot else. Turning on Quartz Extreme with the faster PCI does boost video playback considerably.
If your PowerMac is already getting too slow for your needs this won't fix very much in long-term. It was part of a personal challenge to see how far these old systems could be pushed. I considered the project officially "done" about half a year ago since there's not much left to do unless we get better CPU upgrades or PCI graphics cards (very unlikely in both cases).