The 1GB HD4870 might be advantageous, but bear in mind that a 1GB HD3870 was made, and it made ZERO difference to performance, not a sausage. It might help for the 4870, but the projected price is at least 25% more, so it will scarcely be worth bothering with.
would a 1gb card be more 'future proof'? i mean, right now, games only use 512mb video cards so the 1gb wont really make a difference, but later on, it will once games start using more than 512mb, wont it?
It didn't for the HD3870 - ATI cards don't 'run out' of memory like nvidia ones do. In the same tests where 1GB nvidia cards flattened their 512MB counterparts, the ATI cards both posted the same results, even running current games at 2560x1600 with AA/AF enabled...
