Did you check for firmware updates for that ssd?
The updates fix issues like this. I just updated my drive and the performance went up a notch in throughput.
Is your motherboard firmware, "BIOS" up to date, once again it will help with issues like this.
I hope you shut off the defragger! It will eventually shorten the life of the drive if not kill it outright. Win 7 has "trash collection" or "Trim" to keep the drive factory fresh.
Is windows fully update, there are a lot of updates for win 7. You have to run it several times to get it fully updated.
Are you using an anti-virus? I use Microsoft Essentials along with Malewarebytes and win 7's firewall. That stops most of it...but it is the nut behind the wheel that brings in the virii...