As you know, the arrival of hard drives with higher than 2 TiB / 2.2 TB capacities poses a few compatibility problems, especially in Windows. You have to go from LBA type addressing to Long-LBA and MBR partitioning has to be abandonned for GPT.

To use such a drive as a secondary drive, Windows Vista and 7 are compatible, as is Windows XP 64-bit. Windows XP 32-bit doesn’t support these drives correctly.
To use such a drive as your primary drive, you’ll need to use either Windows Vista or 7 64-bit, as well as a UEFI bios.
What does this give in practice? We got our hands on a Western Digital Caviar Green 3 TB (WD30EZRS).
Secondary drive in Windows XP 32 bit
This configuration isn’t supposed to be supported… something we can confirm. Windows XP 32-bit SP3 only recognised a 746.51 GB drive in our case! Note that
Paragon has announced a get around for this problem, but it won’t be free.

Secondary drive in Windows 7 32-bit
This time, Windows recognised the hard drive as having a capacity of 3 TB, or more exactly 2749.39 GiB (Windows displays in GBs but processes in GiBs). By using MBR partitions, you can create a first partition of 2048 GiB, but the remaining space isn’t usable. If you convert the drive to GPT, which requires the prior deletion of existing partitions, you can use all 2794 GiBs.


Primary drive in Windows 7 64-bit
To install and then boot on a drive using GPT, you need a UEFI bios and Windows Vista/7 64-bit. With a 32 bit installation DVD or without the UEFI BIOS, the partitioning will be in MBR and only 2048 GiBs will be usable. Although the drive is already partitioned in GPT, Windows will refuse to install anything over the top.

After activating the UEFI Boot option on the bios of our Intel DP55KG motherboard, the motherboard started in UEFI on the DVD and the installation took places in the standard way, whether in IDE or AHCI, and on a single 2794 GiB partition if desired (after having created a 2048 GiB partition then stretching it). If you deactivate the UEFI Boot on the motherboard after installation, the BIOS won’t be able to find a bootable peripheral.