Changed SSD and so far so good. Changed a brand new M500 for a brand new 840EVO. Could be coincidence????Try a firmware update on your SSD,also try a different SSD to rule out any issues with that during install,if you are using your SSD as cache drive to a normal mechanical drive remember to set your BIOS to RAID before install.
PS I never use cache drives. The SSD is always the system disk(in my computers).