After making RAID-1 and recovering the system on it, windows experience index showed me 5.3 for HDD performance instead of 5.9 in non-RAID configuration. HD Tune software showed me less average read speed than non-RAID setup. Installing Intel Rapid (Matrix) Storage Manager and drivers made windows experience index jump to 5.6.
When I created RAID-0 array and recovered OS on it, I received 5.9 windows experience index and almost as twice boost in HD Tune read speed. But this kind of setup is pretty dangerous.
ASUS G75VW (Intel Core i7 3610QM, 12 Gb DDR3-1600, nVidia GeForce GTX 660M 2 Gb, 2x750 HDD, 3D Vision)