Which drive bay to install single HD in MDD G4 ?

I'll assume that you didn't have those 4 drives connected to an Ultra ATA-133 PCI controller card. If I were installing a single hard drive in a G4 MDD, I'd mount it in the rear carrier. That enables a direct connection to the faster onboard ATA-100 bus. Drives in the front bay are typically connected to the slower onboard ATA-66 bus.

I don't know your reasons for selling it but make sure you really no longer have a need for it 🙂
It can do service as a file or print server, a simple machine for the kids, backup in case another mac fails, etc. Just throwing that out there as i have seen a lot of old Macs being thrown out for wrong reasons.

This might also be useful: http://appleserialnumberinfo.com/Desktop/TnR/Tips/PPC/PPC.php

Jeff,

Are you sure about the faster 100 MHz bus speeds on the rear drive carriers?

I have had a G4 MDD for 10 years and have done many upgrades to this over the years and never, EVER knew this.

I have only two internal HDs installed. You mean, I could've put my everyday boot hard drive on the faster bus and select that drive as my regular boot drive?

Does the Master/slave relationship, when connecting these back up, change or stay the same? Would my preferred boot HD on the faster, 100 MHz bus, in the rear carriage, need to be set as the Master drive?

Yes - the faster Ultra ATA-100 bus connection is at the rear of the motherboard and the connections for the two slower buses (Ultra ATA-66 for additional hard drives and ATA-33 for optical drives) are located near the left front corner (ATA-33 on the left and ATA-66 on the right). From EveryMac.com's description of the 1.25 GHz DP model: "It has four internal 3.5" drive bays -- two Ultra ATA/66 and two Ultra ATA/100 -- intended for hard drives and two external 5.25" drive bays intended for optical drives."

Thanks, Jeff!

I might swap my main boot drive from that Mac and move it the rear carriers and hook it up to 100 MHz bus connection. Hopefully this will work out.

😉

I'd mount a single hard drive in the bottom of the carrier, so it is closer to the chassis wall. This provides more separation between the processor heatsink and the top of the hard drive - both of which give off heat. Even with the lower fan blowing across the heatsink and providing air circulation to the rear of the case, I'd still prefer keeping as much space between them. Since the G4 MDDs support Cable Select, take advantage of the convenience it provides. It was designed for ease of assembly for system builders, whereby each drive - HDD or optical - could be configured the same and without regard for the actual mounting position in the case. With a ribbon cable supporting Cable Select, the detection or non-detection of a ground signal at pin 28 enables the drive to self-configure as master or slave respectively. When you're assembling hundreds of units, this speeds up the process significantly.