I got the stock 4gb, would I feel much of a difference with 8gb? will it void my warranty? & is there good compatible RAM for this under $100.00? or under $150.00? I am looking for the chapest possible but dont want it to be incompatible either. or would getting an external monitor be better? would upgrading RAM be more effective than a SS or solid state drive? I am using Adobe CS5 software, indesign & photoshop.