This is an easy question, I just want to get it out of the way...
Considering the SATA interface of a raid array of a number of drives, is the maximum speed of the array capped by the transfer speed of a single SATA (1, 2 or 3) connector or is this “cap” = (number of drives) x (transfer speed of interface)? … or is it somewhere in between?
Suppose you have a RAID0 array of two Intel SSD's who's r/w is 250/70, will a SATA 2 interface (300Mb/s), not create a bottleneck? (I am thinking the "burst speed" might be slowed down, but I'm not sure how burst speed compares with SSDs)
Is it necessary to switch to SATA 3 for the SSD I mentioned? Is it necessary to switch to SATA 3 for SSDs in raid in general?