Does anyone know if this requires low density memory? I have a V100 that has 1 gig in it (4x256) and I'd like to upgrade to 2 gigs (4x512). Anyone want to sell 4 sticks? Also, has anyone ever tried upgrading to 4 gigs? I saw a reference to the 550s and 650s being able to use 1 gig DIMMs. That doesn't help me though as mine is only 500mhz.