So far, everything is amazingly snappier. One thing broken: canoscan N650U no longer can be found in classic photoshop 5.5 plugin, however, it can be accessed just fine from within OSX using vuescan, which I just downloaded to try.
CONFIGS:
G4/400 Yikes PCI, with newly installed ATI radeon 7000 PCI video card, 1 GIG ram, 3 large drives, non-standard Sony CDrw. This is the lowest end G4 possible.
PROCEDURE:
1. Cloned existing 10.1.5 over to spare 12 gig partition. Inserted OSX install disk 1, and did an update install rather than a clean install. Everything went fine, although install was unbearably long, probably closer to an hour...similar to windows install ...blah.
2. restarted, all settings retained fine, accessed internet, etc. without problem.
OBSERVATIONS:
1. updating the classic partition renders it unusable for the original OSX 10.1.5, so prudence would dictate using a cloned copy of your classic folder.
2. SPEED! weeeeeeedoggies! Now, the question is how much is related to optimizing? Don't know yet, but this is faster than any previous optimizing boost. Mainly explorer and window opening, app opening noticeably faster.
3. Freehand 9 in classic starts INSTANTLY. huge speed gain in classic just in general. So far, haven't checked all classic apps, but they all still work except the previously mentioned canon plug in.
4. Fonts appear to render more clearly. But this could be from the video card upgrade.
5. improvements to calculator is amazing....has advanced feature that shifts to full scientific calculator as well as running a paper tape of computations.
6. Improvements to Mail is good as well, you have separate tabs for the POP server so you can directly manage remotely stored mail...sweet.
7. accounts are now accessible through system prefs.
8. New Cds and DVD prefs pane
9. Default folder, Diobatin and Tinkertool still appear to be functioning.
10. startup disk prefs pane seems improved in both appearance and speed.
11. Address book looks very interesting, haven't played with it yet.
12. Unfortunately, it installs ichat by default, with a suspiciously AIM looking icon. Sure enough, you can use it for AIM. bleh.
13. Epson 740 functions just fine.
14. My internal fujitsu DynaMO 640 works like a charm.
I'll do more testing later....