For that particular model laptop only: tell me about the rails that were attached to the hard drive. Did they also fit the SSD? Did you need something else to snug up the SSD in the drive slot? Any ...
Got Lenovo T430 with 4 Gig of PC1600. See that the 8Gigs are available for a decent price and not much more than 4 Gigs sticks so would prefer to go with 8Gigs.