I got a Samsung 840 Pro and I reinstalled windows. Before this, I had a score of 4.5 with my old HDD drive. For Samsung I got a shameful 5.9 (since this device has the lowest score, the whole laptop is graded as 5.9). Why? On Windows 8 which I had installed for a day, the rating was 7.7 (for SSD).
My system is Toshiba Qosmio x505 with Intel P55 chipset. Win 7 32 bit. I have the SATA AHCI driver installed.