Which one is better ? GPU - Graphic Card?

Yes the Ti version is better...and yes there will be a difference in the 2GB version vs. the 1GB version.

Your machine can take the advantage of the higher ram . Not all games can use 2GB of ram but many of the high end games can. If you note they both have 384 CUDA Cores and you can OC the the 2GB version to a higher clock speed. The 2GB version has a bit better rating among gamers.

that graphic card is on edge fast enough so it would actelly be usefull with 2GB vram instead of 1GB.

i would say that its better to take the ones with 2GB instead.

but ofc its not like your gonna notice " OMG ITS SO MUCH FASTER" it would be a bit better then

the 560 TI is quite a lot faster then a non-TI one

a overclocked 560 is almost as good as a 560 TI (a rather highly overclocked 560 that is)

then ofc you got the gtx 560 TI 448 or 448 core which is faster too, it performces about as good as a 570

the asus direct Cu2 cards are great, i got one myself but a 6950, cool, quiet, clocks like a dream and so far i never reached over 65C even with it maxed clocked currently.

downside is that its HUGE

bypass for the MSI R6850 because it promises more desirable skill than GTX 465 ! and is OC version also ! btw your reveal screen is highly small so any of those playing cards are overkill ! yet in any case R6850 is more desirable suitable in all aspects ...