990FX certainly does support TRIM on either the standard Microsoft driver or AMD's AHCI implementation. Support was added years ago with the 700 series Dragon platform if I recall.

Yes but as far as I know it only works for single drives, if SATA is configured in RAID mode, if you make a RAID array it wont pass the TRIM command,

AMD doesn't have TRIM support when using RAID. At least not yet anyways. Intel does though. But you should be ok using the Samsungs in RAID. Magician has an optimization tool you can use for when TRIM isn't available.

Unless you have a SPECIFIC goal in mind for throughput in a certain application, SSD RAID0 does not seem to benefit boot times or game loading times.

Unless you have a SPECIFIC goal in mind for throughput in a certain application, SSD RAID0 does not seem to benefit boot times or game loading times.

I have decided to build up Raid 0 with 5x Corsair Force GS. 2500mb/s read and 2000mb/s write, with LSI 9211 controller. My X48 chipset and DDR3 memory guarantees that this bandwidth is not supressed by any kind of bottleneck. Boot time is about same, true, but loading times are almost immediate. I can also notice different behavior of system - like the clock near cursor is not constantly there when loading data, but they are flashing very fast, as its certain that CPU have to take a break once data from drive are loaded... 🙂

Does the LSI SAS 9211-8i have UEFI firmware, for supporting windows 8 secureboot and fastboot?