This!
I ran out on Skyrim with the HD packs with my old GTX 295. It wasn't a slight dip.. it goes from playable to 0 in a blink of an eye.
Been playing around with Skyrim mods and all was good until I installed the Texture Pack Combiner, some stuttering started.
Different setups-maybe page file setups result in different scenarios as my fps didn't hit zero, it didn't, it bounced up and down from 60fps to ~15 fps or so when it ran out of vram.
Either way you look at it, 2GB at the very least is perilously close to running out@2560 and the full fat title hasn't released yet.
More assets are inbound, no one knows if the full ultra settings are actually applying yet or auto downsampling is occurring afaik.
High tesselation/advanced lighting/weather??? might still have a role to play.
I implore everyone to wait it out for the full game before binning their current hardware. Hard to base anything fully on a beta.
+1
Or basing a purchasing decision on beta status.