Your drive is fine and appears to be operating above advertised speeds.
Advertised speeds for OCZ drives are with ATTO and AS-SSD benchmark software.
AS-SSD & CrystalDiskMark use highly incompressible data to test Read/Write speeds.
ATTO uses highly compressible data to test Read/Write speeds.
Advertised AS-SSD speeds for your drive are "up to" 175MB/s Read and 60MB/s Write.
If you are looking for the advertised 500/450 Read/Write speeds then you have to benchmark with ATTO.
Here's the link for the spec sheet of your drive: http://www.ocztechnology.com/res/manuals/OCZ_Solid3_Product_sheet.pdf