Over a year and a half has passed since Western Digital launched its 2TB hard drives. Since that time we've seen prices drop but the maximum drive capacity has stayed firmly fixed at 2TB. A few months ago Seagate announced a 3TB model of its Go Flex desktop hard drives, but it hasn’t been until now that 3TB capacity has been available as an internal disk drive.
There are a few reasons why 3TB drives haven’t materialized.
We covered the issues in detail during our look at Seagate’s drive, but in a nutshell the problem is that 3TB drives have to be formatted with GPT (GUID Partition Table), the successor to the Master Boot Record (MBR) partition table system that has been with us for most of the history of the PC.
The MBR and GPT both manage the system boot
Unfortunately GPT has patchy operating system and hardware support. Windows 7 can read GPT for example, but systems that have a BIOS can’t boot from a GPT formatted drive.
This effectively means that you cannot use a 3TB drive to boot a PC. It can only be used for storage, and only if your hardware supports the drive. To this end Western Digital has come up with a novel solution, shipping its 2.5 and 3TB drives with a Host Bus Adaptor (HBA) add-in card. This is a x1 PCI-Express Rocketraid 62x, which we reviewed a few months ago. As a standalone product we weren’t that excited by the card, but in this bundle it makes a whole lot of sense.
Several issues are dodged by using the HBA card. The first is patchy driver support for Serial ATA controllers and drives greater than 2.19TB. The second is the way in which Windows deals with Advanced Host Controller Interface (AHCI) drivers.
When you install Windows it installs drivers based upon how you have set up your hard drives in the BIOS. If you have the controller set to IDE Windows will install IDE drivers and if it is set to AHCI it will install AHCI drivers. If you install windows with only IDE drives, then switch to AHCI Windows won’t have the appropriate drivers and cannot boot up. There are ways around this, but they get quite complicated and hacky.
By including the rocketraid card Western Digital can guarantee that someone can buy one of its 3TB drives, install it and have it work as a secondary drive. It does eat up a x1 PCI-Express slot, and our review sample only shipped with a half-height blanking plate, which will need to be removed before you install the card. But it works, which is the main thing when dealing with ‘exotic’ hardware like this.
Of course the card adds to the cost, with 3TB models costing $309 RRP (2.5TB models come in at $239). Considering that you can pick up 1.5TB drives for under $100 it does pose the question of why you'd pay more per gigabyte for a drive that isn’t fully supported under Windows. The only situation we can think of here in the PC Authority labs is one where you absolutely need as much storage as possible, only have two 3.5in drive bays and are running an SSD or 10,000rpm Velociraptor as a boot drive. Otherwise two 2TB drives would be a much better option for compatibility.
While it is noble for Western Digital to implement this workaround to get 3TB drives running, don’t expect a flood of products. Until the much delayed BIOS-replacing UEFI technology starts appearing on motherboards (currently UEFI is almost solely used by Apple) the hoops needed to jump through to use a 3TB hard drive just really aren’t worth the extra cost and effort involved.
The 3TB Caviar Green hard drive ships with this Highpoint Host Bus Adaptor to ensure compatibility.