Congrats, that's a great old machine for $50. I'd also suggest you upgrade the video card. A PC Radeon 9600XT might be a good bet... I imagine you can flash it with the Mac AGP drivers, then clock it back up with ATIccelerator II. Check that out first though, I may be wrong (about the flashing). Otherwise, Mac OS X's GUI will be somewhat choppy. My beige with a 500 MHz G4 ran kinda choppily when hiding windows with the yellow middle button (used to be called "collapsing in OS 9, no ****in clue what they call it now). I enabled Quartz Extreme via the PCI-Extreme hack and it runs smoothy up till around 1600x1200 where it starts to get choppy with windows filling the screen... I keep it at 1400x1050 anyway. Yours should be fine at much higher res, since you've got AGP.
You won't be able to use Quartz Extreme unless you get a Radeon or GeForce card, because pre-radeon (Rage chips) didn't support arbitrary texture sizes, meaning you wouldn't be able to resize windows.... so.. Apple didn't enable it for them. Makes sense.
Other tips.. get a new HDD... don't bother with SATA, your onboard ATA is fine (unless the size you want is more expensive as "PATA" than is an SATA card + drive).
600mhz is not really attainable with a 7400 G4.
It's been done. It was overvolted, but it's been done.
I think Moto hit a brick wall with the 7400s trying to go past 500, not to mention getting half the 500s to work correctly.
Not exactly. There was a bug in the MPX bus that prevented higher speeds, not anything to do with thermal issues, if I'm remembering right. Hence the reason Apollo used a new architecture... the 7450 was a totally different chip from the 7410 (the 7410 being a 7400 with a die shrink and almost nothing else).
How about a 7410? I would have bought one of these but just got a sonnet upgrade for my cube.
7410 runs a bit cooler, though they never used it for anything above 533 MHz in the Mac.
If you want higher clocks, you need a deeper pipe... the 7450.
