SanDisk Extreme SSD 480GB not working well on my Macbook Late 2008

I bought a SanDisk Extreme SSD 4 months ago. I thought it was faulty so I exchanged it for a new one. After using it for a few weeks it doesn’t quite work as well again. My computer freezes and music and videos would stop every few minutes. After changing back to my old HD, the computer works again.

I’ve updated my OS to the latest version and have updated the firmware in the SSD. Does anyone know if this is a known problem? Can I get a refund or a different SSD from SanDisk? I know I have a 3 year warranty, but I don’t know if it would cover something like this.

My computer details:

 Model Name: MacBook

 Model Identifier: MacBook5,1

 Processor Name: Intel Core 2 Duo

 Processor Speed: 2 GHz

 Number of Processors: 1

 Total Number of Cores: 2

 L2 Cache: 3 MB

 Memory: 8 GB

 Bus Speed: 1.07 GHz

SATA slot:

  Vendor: NVidia

  Product: MCP79 AHCI

  Link Speed: 3 Gigabit

  Negotiated Link Speed: 3 Gigabit

  Description: AHCI Version 1.20 Supported

any refund would ahve to come from the place of purchase. 

That said some others had similar issues with that model of MAC. Disabeling sleep resolved the issue. see the thread linked below.