so-dimm

I have an Sony VAIO VPCEH28FN one slot has 4gb module and one slot is free so I want to add another 8 gb On sony's product page here its mentioned that Pre-installed/Max 4 GB (4 GB (SO-DIMM) x 1) DDR3 SDRAM*2 (upgradeable up to 8 GB*3) SO-DIMM slots DDR3 SO-DIMM slots (Unused Memory...