Hy. I Have Sony Vaio i5 sve14137cvw Model. It has 4GB Ram at the moment. And I Intend To upgrade it. It says In It's specs "Upgradable Upto 8GB". Does that Mean That I can add only 4 more GB Ram To make a total of 8GB Ram. Or I can add an 8GB ram in Unused slot and Make it a Total of 12GB?