GPT or MBR?

[zaphox]

Hi,

I'm running Vista 64 with 2 * 250GB SATA HDs. The first disk was obviously formatted during the installation of Vista.

In disk management I went to format the 2nd disk and it says I have to initialize it first. It gives me the choice of using Master Boot Record (MBR) or GUID Partition Table (GPT) and advises me GPT may not be compatible with older OSs and is best for very large disks (I think 2TB was mentioned!)

Can anyone advise me on the advantages/disadvantages of GPT?

[aidanjt]

GPT if you have an EFI based motherboard, MBR if you have a BIOS based motherboard. You can mount GPT disks on a BIOS based system once the OS is loaded but wont be able to boot from it.

[directhex]

GPT is significantly more featureful, but aidanjt has pointed out the major blocker - it's only bootable from EFI systems (e.g. intel macs, itanium kit), not BIOS-based

[peterb]

One of the advantages of a GPT is that you can have many more partitions than those offered by an MBR system. (MBR offers 4 primary partitions, one of which mmay be extended, with extended secondary partitions in each - but each partition table, although only 64 bytes long, uses up 63 sectors of the disk - not particularly significant in terms of large disk but still...)

So for a secondary disk on a pentium based system, a GPT really isn't (IMHO) worth the bother. There is no easy way of converting from one format to the other without losing the data (or backing it up first) as it requires a reformat.