WD My Passport Essential 1TB slow transfer speeds

[Will-Bly91]

Hello, i have been having problems getting my portable hard drive to transfer as it did when i got it. i am running windows 7 i7 2600 3.40GHz with 2 USB 3.0 slots in the back. I have previously copied a folder a little over 6 GB's to the drive from my computer and it took about a minute to a minute and a half now i am looking at a transfer rate of about 32 mbps. it takes about 10 minutes to transfer a file of 300 mb's which before, would have transfered instantaneously. I plugged it in the other night and windows 7 asked me if i wanted to fix the drive so i clicked both options and let it do its thing for about 24 hours (4 P.M. today) and i'm still not getting the same transfer rates as before. i have used check drive and says the drive is working properly. i have not changed any settings in the computer at all. also my mobo is an asrock z68 extreme gen3. any ideas on why i am not getting the same transfer rates as before?

 

[Will-Bly91]

any suggestions would be appreciated, would really like to get this thing working right again it's been driving me insane for months. if theres any more info needed i'm more than happy to get it out there