I have the Samsung RF711 which is a i5-2410m Laptop with 2 SSDs (one for OS + Programs and one for storage. As SSD show an overall score of mid 700's
Hopefully the MB bios update will Help.
Didn't look up lartest Firmware for your drive (I see yours is 400i)
General comments. Your 520 uses the SF controller which favors Sequencial data that is readily compressable, so using AS SSD, your Seq read/writes will be lower than advertized (JUST NOT THAT MUCH)