The 460 is def better,no doubt about that.But will it be playing the game smoothly ? no idea what your definition of smoothly is.That is also defined by the rest of your systems hardware,like your cpu etc.But the 460 is good enough to be playing the game at High ( atleast in pve ) with a pretty consistent fps.
will it run smooth as in not choppy or laggy?
No idea but, people have a different definition of what runs smooth for them.Some people call 30 fps smooth,i call it choppy..60 fps is smooth imo.But your other hardware is important too,especially your CPU.You can have the best gpu but if your cpu is lacking,you will still be playing choppy.So rather post All your specs,and maybe someone can jump in who actually owns a 460.But all in all a 460 should be more then enough to run Gw2 at high, (Pve speaking).
i dont know too much about computers but the computer im buying from my friend has
1.5 TB Western Digital Black hard drive and a Corsair Force 128GB SSD
GTX 460 card
The ASRock motherboard
and thats all i know