What Plextor told me was that certain manufacturers that aren't Mac certified are not able to take advanatage of all of the features. Please read Plextors response below.
"Scott, although the RMA has been created, it appears that your return request is past the 14 day grace period which would disqualify you for a refund. According to your invoice, the purchase was made on the 3rd of this month and the date on your initial email in regards to this issue is 2/23/2012. Please click on the link below for our full return policy.
Regardless, your PX-512M3S is still covered against any hardware defects for 5 years from the original purchase date. Also, please be sure to contact our technical support center for assistance with any technical issues that you may have. For Mac OSX, Apple has decided to not include support for any hardware which has not been Mac certified. This includes, but is not limited to, the option to enable TRIM, which can affect your SSD's performance. Please click on the link below for instructions on getting around this."
BTW...I didn't receive the drive until the 14th of Feb.