Ya some laptops you cant upgarde teh RAm or they have already filled the RAM slots with small RAM chips and so you have to replace both slots to get the upgrade you want.
You could buy a $1000 laptop and then upgrade the RAM (checking that you can before you buy) - you shoudl also get a dedicated graphics card - it will help enormously with PSCS3
Im a fan of Dell because you can build it with what you want but really Its probbaly cheaper in the long run to go with more than you need right now than to upgrade later so if you can stretch to the 4GB then do it.
JMO
