Confusion about SATA and “SATA2” specs.

[GotNoRice]

I see SATA being referred to as having a speed of 150MB/sec and then others refer to it having a speed of 1.5Gb/sec. I see “SATA2” being refered to as both 300MB/sec as well as 3.0Gb/sec.

Now last time I checked, there are 8 bits in a byte, not 10. 150MB/sec would equal only 1.2Gb/sec. 300MB/sec would equal 2.4Gb/sec

What is going on here?

[unhappy_mage]

There's 8/10b coding on the protocol. All four of those terms are accurate, but they're talking about different things.

8/10b coding means there are 10 bits sent for every 8 you request to send across the bus. So the signaling rate for sata2 (how many bits are send across the bus) is 3 gigabits, but the data rate (how many bits/sec you care about) is 300 MB/s.

http://www.hardfolding.com/ftag1.php/mem/150072.png (http://www.hardfolding.com?go=38&tm=33&id=150072)http://www.hardfolding.com/utag.php/mem/1392.png (http://www.hardfolding.com?go=36&id=1392)