SATA 3.0 Speeds

[Krovos]

There are 8 bits in a byte. SATA 3.0 boasts speeds of 6gbps. My calculations would tell me that "6gbps /8 = 750MB/s". This unfortunately doesn't seem to be the correct answer, as every source I have found on the internet is telling me "SATA 3.0 = 6gbps | 600MB/s". What am I missing here?

 

[beers]

8b/10b encoding, counting the extra encoding bits means 6000/10=600 MB/sec

Then you have protocol overhead which usually gives you around an effective limit of 550 MB/sec or so.