Are SATA controllers capped @ 3Gbps?

[Onceler]

Or is it just 3Gbps per channel and drives in RAID can exceed 3Gbps?

 

[Rubycon]

3Gbps per PORT. Bandwidth is limited by command overhead, IOP hardware (if applicable) and interface bandwidth usually in that order.

 

[MalVeauX]

Or is it just 3Gbps per channel and drives in RAID can exceed 3Gbps?

Heya,

Per channel. This is why you can have several drives together that can achieve gigs per second, rather than just megabytes per second. As it is, normal SATA drives barely even saturate 1.5Gbps SATA channels, as they sit around 80ish MBps sustained which is just over half the channel's ability. 3Gbps channels are just way more than even our fancy SSD's can handle. They can only crack that barrier on burst reads. But for general use and sustained use, they don't saturate it. But, they will soon, because many are easily hovering in the 200+MBps range sustained reads. So that's why they're pushing the new 6Gbps channels. It's still SATA of course. But this way it'll be much more difficult to saturate that as better SSD's hit the markets. HDD's will never saturate the SATA 3Gbps frankly.

In RAID, it works because each drive has it's own channel. That's why you can get huge speeds even through the channel cap says you shouldn't be able to go over a specific number.

Very best,

 

[aggressor]

Current SSDs are at the cap of SATA2 with their read speeds, as shown here: http://www.anandtech.com/storage/showdoc.aspx?i=3702&p=9