I don't know if the problem has been fixed but when i brought 2 of these 640gb green drives to run in a RAID0 2 years back, they turned out to be real dodgy causing random system lockups, I would be playing an online fps game having a firefight and my system would suddenly freeze for a short period and then unfreeze only to find that I have died.
It took me three months of hair pulling and stress levels that nobody should ever experience, for me to diagnose my random lockups and i couldn't believe it when it turned out to be the WD Green hard drives causing the problems all along, I RMA'd the drives thinking that one must be faulty but the new replacement drives were no different and my random lockups remained, I ended up putting one of the useless things in my mothers computer thinking the drives had a problem running in RAID0 but my mother then started having her Windows install, Kiodia and other games locking up randomly all the time.
I assumed that the problem would be fixed quick smart but If you do a google search you will see many posts about random lockups with everyone involved running a green drive scratching their heads in confusion, another major hard drive manufacturer has been having a very similar problem with their drives, I have come to the conclusion that the green drives are useless for running windows and playing games.
I would recommend that if you already own one and are having this problem that you only use it as an external backup drive!
WIZz