Gibbo is a salesmen, I would prefer to trust neutral sources instead of which there aren't any showing a 1280MB GTX570 struggle in anything.
I don't really know enough about BF3 to know how taxing 60 players is but I don't see how that can be benchmarked fairly unless you coordinate 60 people to do exactly the same thing twice for benchmarking purposes. For all we know on the 1GB run there could have been considerably more particle effects etc in play which lead to a more severed dip in fps. Lag can also affect frame rate and perceived performance.
Unless you have a severe lack of system memory then the page file should not come into play, even with a 3GB Radeon if you have a lack of system memory and disable the pagefile the game is going to struggle primarily because the game runs out of system memory, not video memory.
Even those with 3GB Radeons if you go to screen resolution and click advanced settings you will see that Windows has reserved some "shared system memory".
I thought every card except 680 used page file instead of actual RAM and that's where the issues are? IIRC system memory (before 680) couldn't be utilised and that's why people are talking about big amounts of VRAM?