Lack of availability (now) as we can no longer source the AS331 v1.5 JMicron / JM20330 IC based IDE / SATA bridge adapters. AND because they were occasionally problematic booting back and forth between OS 9 and OS X in the Lombard. The Compact Flash approach WAS the best overall approach when previously tested back in November of 2021. [Reference
http://macos9lives.com/smforum/index.php/topic,6065.msg45769.html#msg45769] The AS331 v1.5's were great when dedicating the Lombard to either OS 9 OR OS X - but not both. I really do like the 7200 RPM HDD results!
Have also been testing (again) the MCA004 v1.3 JM20330 IC - based adapters (as they appear so similar to the AS331’s) in both the Mac Mini and the Lombard and they are problematic, even in single OS - boot situations.
All of the above led me to (Hail Mary) test the faster, 7200 RPM HDD… and I was surprised. Perhaps best to stick with the older spinners (yet faster, 7200 RPM) drives in these early PowerBooks?
BUT YES… if you can find one of the AS331’s (or even the MCA004 if you don’t mind weird) in a single OS setup, they are faster-est.
Have also considered the “unbranded IDE to M.2 adapters” (as mentioned by teroyk here above
http://macos9lives.com/smforum/index.php/topic,6671.msg50299.html#msg50299 ). But based upon his negative report on use in the PDQ - that’s a no-go in the Lombard. But I believe IIO uses them in Mac minis and I’ve asked him to provide QuickBench results to compare to the AS331’s - because I may need an option for future G4 Mac Minis here.
Note: I currently have six G4 Mac Minis (of varying CPU speeds) using the AS331’s. Here are QuickBench results from the slowest, lowly-est, dual-boot 1.25 GHz Mac mini.