i have a 2.8 imac with 1gb ram. . .i use photoshop,etc., and i'm well aware that the only thing holding back the speed of my computer is how much ram i have. i'm going to max it out at 4gigs. apple's ram is ridiculously expensive, so before i even bought the computer i decided to upgrade the ram through 3rd party. any tips on 3rd party ram? i can get 4 gigs (2x2gb) for around $170 online, but i'm just wondering which brands were the best, or if it really makes a difference.