User who After upgrade to R211 Feel Slow come in here.

[drlucky]

best thing to do will be to create a backup image of your PC then secure erase the SSD. once secure erase is done then reimage the SSD. 

here is some more information about getting the SSD performance back.

http://forums.sandisk.com/t5/SanDisk-Extreme-SSD/HOW-TO-GET-YOUR-SSD-PERFORMANCE-BACK/m-p/281740/highlight/true#M641