I have two slots of 256 mb ram for a total of 512 mb. I do a lot of digital photography and so I need more RAM -- I am about to buy a 512 stick ($41) and keep a 256 stick in there for a total of 784 mb. Do you think I'll notice any difference between 512 mb and 784 mb given the amt of money I am spending? I'm planning to buy a new computer in about a year.