Hello, I have a HP Pavilion desktop computer with 2.6Ghz AM2/AM2+ dual core, with four 1gb = 4gb of ddr2-6300/5400 ram, 320GB 7200rpm 3gb/s sata2 hard drive. I was just wondering if I could install two 2gb ram sticks and leave the other 2 slots with 1gb a piece, leaving me with 6gb of ram. I was wondering if I need to keep it all the same speed (6300 or 5400) as well as keep the ecc and brand all the same. Also what aspects of computing would upgrading my ram helpful in. I basically have multiple windows/tabs for internet, youtube, email, perhaps word and World of Tanks. I have 64 bit Vista, which I plan to upgrade next year to the new MS o/s 64 bit. I basically want to get more ram in their for any future programs or games that might need more ram.