I recently bought a 3TB Western Digital Green internal hard disk, but discovered that I could only access about 768GB of the capacity on my current desktop PC. After some investigation, I've traced the issue - bizarrely - to my motherboard. For example, if I connect the drive via a USB-SATA bridge (so I'm not relying on motherboard SATA, but everything else is the same) the problem goes away. The drive works perfectly on another machine on internal SATA. Using a different internal 3TB drive on my machine, however, shows the same problem - though a 2TB drive is fine.
Also, I've updated to the latest BIOS and motherboard drivers and it made no difference. I've also tried formatting both as MBR and GPT, which also made no difference. I need GPT to access the full 3TB capacity, of course, but I tried both anyway.
Initially I bypassed the issue by formatting the drive while using that USB-SATA bridge. Windows reported the full capacity for the partition then [when the drive was connected via motherboard SATA again], but locked up when I tried to write more than 768GB of data to that partition. That suggests Windows 7 is failing to do all the checks it should to ensure a partition really is accessible, of course, but doesn't explain why the limit exists.
The motherboard is an ASRock N68-S3 UCC.
Interestingly, there's a FAQ about what looks like the same issue on the page I linked, but the solution - use Windows 7 SP1 - can't be correct. I already use Windows 7 SP1.
I've sent a support request to ASRock, but I've not received a reply other than to confirm they received the request. Even allowing for the new year, it has been long enough that I figure they don't intend to answer.
Before giving too bad an impression - I've had this board (with an Athlon 2 X4 640) for a few years now and been pretty happy with it. It was bought as a budget board, and it did the job expected of it very well. Recently, I've decided it was time for a new, slightly higher-end board and processor, and this 3TB drive has really just pushed me to place the order a little earlier.
Even so, this "problem" board and processor will live on. It's not a bad board in general, it just has some SATA-related oddness.
Speaking of which, two other SATA-related oddities on this board that may be related...
- Windows identifies all my SATA devices as SCSI devices in Device Manager.
- When I plug in an eSATA drive, I don't get the option to eject it from Windows - it has to stay plugged in until I switch the machine off (so I tend to use USB instead).
So - why can't my ASRock N68-S3 UCC based machine access the full capacity of 3TB hard drives? Is it something I could fix (e.g. a BIOS setting that I have somehow failed to spot)?