Downgrading quad G5 to 40GB SATA - Kernel Panic

Question

Howdy folks - I own a G5 Quadcore that came with a 250GB SATA HD. I purchased a second drive (both are Western Digital Caviar SE) and installed it as my backup drive. Everything works great, no issues.
I bought a Western Digital 40G SATA (also a Caviar SE). What I want to do is take out my 250's, put this 40GB in and install a base copy of OSX 10.4. This is so if I have to take it in for repair to CompUSA, those pinheads won't have access to, well, my life. I had a G4 that lost a power supply, and had to take the whole PC in. So I decided I'd never leave years of documents, images, emails, finances, etc, in the hands of the 'techs' at CompUSA. I put an 8GB drive in that G4 and installed OSX on it. So if I ever had to do that again, I'd simply swap drives and bring it in. They have a fresh copy of OSX to test my machine with, I have peace of mind that I still possess my data.
Anyway, I'm trying to do the same thing on this Quad. So I bought the smallest HD I could find, this 40GB WD SATA. Here's where my trouble starts:
I stuck in the OSX install DVD. I shutdown the G5. Unplugged both existing drives, attached the 40GB. Rebooted, held down the C key, after the gray apple logo appeared, I got a kernel panic. Tried again, same issue.
Fearing the drive could be bad, I hooked the existing primary drive back up, along with this new 40GB, rebooted to the OS on the 250GB. It found the blank disk, I initialized it. Ran verify disk, everything checked out A-OK. Shut down again.
I unhooked the primary 250GB, and left just the new 40GB hooked up. Rebooted again, held down the C key, kernel panic at the same spot.
At this point, I just hooked my two 250's back up, rebooted into the HD, and all is back to normal.
So, is there some type of incompatibility with these 40GB drives? Are they -too- small? Any reason why this could be happening? None of the drives are jumpered, so not sure what else to check. Seems like my other Macs I could toss in any blank drive, then boot up with the CD, format, install, everyone was happy.
Any suggestions?
Quadcore G5 2.5Ghz   Mac OS X (10.4.4)  

Answer 1

I don't know why the 40G didn't work, but I like your reasoning. If you're stuck with that drive, and don't want to spend anymore money, try this:
Install your normal boot drive as primary, the 40 as secondary. Boot up, then use Carbon Copy Cloner to make a bootable copy on the 40G drive. It might take some fiddling if your current boot drive is more than 30GB, but you should be able to limit what it copies to just the essentials.
Then try to boot the clone. If it doesn't work, cut your losses (in wasted time) and get a new 160 0r 250 WD drive ($85 and $110 respectively) just like the PowerMacs come with. Newegg has the 250 for $103 plus shipping.
Before I shipped my PowerBook back for service, I cloned the drive (and ran the clone on an iBook for 3 weeks), cleaned everything off the internal drive but the basic OS. Of course, that wouldn't have been an option if the computer wasn't runnable. It had a splotchy display, but ran fine.