Blu-ray is not necessary. But there is also a small process difference in both: S02 has 2.30Ghz whereas S03 has 2.40Ghz. Also S02 uses DIMM type RAM and S03 uses SODIMM. So is there any big diff. in there performance due to Ram or Clock. Also is win 8 a success, I had read somewhere that win8 consumes more memory than win7 (tested with windows performance rating test).