70€ each? Proves my point! That's a bit north of $150 US for both chips, and only a marginal performance improvement. More than I'd pay, although maybe if I had the time and your skills I'd reconsider. It
is a cool idea...
If I were you, and was looking not only for something unique, but also for as much performance as I could wring out of a G4 system -
I'd be looking for an MDD. Here's why:
- faster system bus than the Quicksilver (167 MHz vs. 133 MHz)
- more RAM capacity than the Quicksilver (2 GB vs. 1.5 GB)
- onboard FireWire-800 support on the dual-1.42 GHz FW800 model
Just make sure you get a dual-processor model of 1.0 GHz or better; the MDD also came in single-CPU variants and anything less than 1 GHz has a slower system bus (133 MHz).
Potential caveats, however:
- MDD power supplies suck. If you get a working one, it won't be working for long. The good news is, you can replace the original PSU with an ATX unit - commonly done (done it myself) and there's plenty of help available on this forum and elsewhere to accomplish that.
- The MDD is just a different beast from any PMG4 that preceded it, and firmware might be an issue. You'll have to upgrade the firmware on any G4 system, in order to run a 7448. There is proprietary firmware out there from manufacturers that produced 7448-based upgrades, but the thing is: none of those upgrades were ever designed for the MDD. Only Sonnet ever made a CPU upgrade for the MDD (and its cousin the XServe G4), and those were dual 7447's. I don't know if: (a) Sonnet's 7447 firmware will allow you to boot a 7448 (but I doubt it); and (b) if the proprietary firmware that's out there for the 7448's will work on an MDD.
So there's that. And then, there's this: dual Quicksilvers and MDDs used 7455 chips with L3 cache. What happens when you drop 7448's onto that daughtercard with L3 cache? I suppose there's some way to disable the L3. Then again, a 7448 with L3 would be crazy awesome.
Just thinking out loud. I'm done now.