The data sheet says speeds up to 6GB/s, which would mean that this device enables two SATA II SSD's to operate at full speed. Not bad if you've got an internal 6GB/s SATA card with only a few ports.
You're right, that the thing needs to be connected to a 6.0Gb/s SATA port. But it's not going to be as fast as a single disk can be, due to the additional latency (remember, both disks are on a single port, so there's switching involved).
Sort of (comparing specs of the units only), but the SATA port in the systems are only 3.0Gb/s compliant, so it won't be able to run at 6.0Gb/s (always limited by the slowest link in the chain).
Can one sata port support the speed of two SSD in Raid0?
Not entirely, and it's for two reasons.
1. Both of these units are having to switch one port for 2x drives (RAID 0 or 1), so there's some additional latency due to the switching (what a PM chip does).
2. The internal ports on the MP aren't fast enough anyway.
As it happens, the Stardom unit is only good to ~200MB/s (sold by Trans Int'l as well). Figure for double that for the 6.0Gb/s version, assuming it's connected to a 6.0Gb/s SATA port (PM chip is built into the RAID on a Chip inside the unit). Unfortunately, that's not going to be the case using the ICH (built-in SATA ports on the board), so you'd be doing good to get ~250MB/s or so (SATA 3.0GB/s hits the wall at ~270 - 275MB/s or so, for a single disk in real world conditions; it's always less using a PM chip due to the latency).
What's with that dial? 10 positions with 4 different settings?!
Think parts availability; it was available and within budget.
