Try running AS SSD benchmark and see what it shows:
http://www.majorgeeks.com/files/details/as_ssd_benchmark.html
Possibly your partition isn't aligned to the 4K sector boundary. This can happen if you cloned a HDD to the SSD instead of doing a fresh install.
Also, you'll want to check that AHCI is enabled in your BIOS (AS Tool will check this for you).
You'll also want to be sure of which channel you're plugged into on your motherboard. Most motherboards have two separate memory controllers and they aren't created equal. Often there will be two SATA ports which are a different color, these are usually the fast ones.
Post a picture of what AS SSD Benchmark finds, and we'll start from that. Also, let us know what motherboard you have.