GUID or APM for G5 and Intel, non-bootable

[macmac]

I know GUID is required to boot on Intel. However, I have a couple external eSATA drives that I want to be usable with both G5 and Intel. I'm currently on a G5 but don't want to have to re-initialize and reinstall the data when I get the Intel, so I want to do it right the first time. They will not contain system software = non-bootable.

These files are streaming-type audio files used in recording and the multi-GB samples that come with certain audio software.

Which is my best bet: do Apple Partition Map, or GUID? I know a GUID will mount on my G5 now, but don't know if GUID can eventually become a problem on a G5, particularly with these types of heavy-access files. I don't want problems down the road with the G5 or the Intel due to my choice.

[unclemac]

I don't know if this has changed with 10.6, but with 10.5 GUID was not required for Intel Macs to be bootable, but was preferred. Let me splain.

Intel Macs will boot GUID, but is a thing or two that won't work as expected. The only one that comes to mind is that you cannot install a firmware update. Not a big deal for a portable external drive, but a PITA for the internal boot drive.

I know this because way back in the first gen MacBook times, my employer had about a half dozen MacBooks that actually shipped with the wrong partition scheme from Apple. Machines worked fine; imaged them with a new OS, users used them for months. During routine updates, firmware update would not run. After digging, found the issue. Had to reformat to GUID, then all was good.

Since you are not booting, I believe you can use either format. Apple recommends APM for all non-start up drives.