1) You just buy the SSD and connect to the SATAII_0 port. In the BIOS, you need to set the RAID mode before you install the OS like win7 or win8, but not other HDD.
2) If you want to buy the SATA 6G PCIE add-in card, you have to buy one at least PCIEx4 card to get the full performances from the SSD and it is not cheap.
3) If you use the SSD for regular usage then you just connect the ssd to SATAII, and you will not feel the difference between SSD In SATAII and SATAIII port. You only can see the differences in benchmark scores.
4) Either Samsung 830 or the 840 pro is great and go for it.
I think I will stay with my MB SATA 3GB at present and forget about SATA 6G card.
I took the plunge and ordered Samsung 840 pro 250 GB, which hopefully will be delivered in a few days time. I will install it as my win 7 system drive.
My BIOS SATA options are RAID and ATA. You mentioned I needed to set the RAID mode before I install win 7. Any reason? What would happen if I leave it on ATA. Perhaps you will be kind enough to explain it to me please?