I only get about 200mb read/writes on my i5 750 system, is this about right or should I be getting faster?
Yep that sounds about right with what I'm getting, it does depends on what program you are using to test it with as they use diffrent tests and ammount of data etc
With AS SSD:

Then ATTO Disc Benchmark (Which is probally what they use to get the 500mb/s stats):
