in some applications/games, yes (ie GTA 4).
i dunno if the athlon 2 x4 will be slighty better because of +2 physical cores over your phenom 2.
also, i heard you can unlock the 2 cores of the phenom 2 x2. not quite sure. if you already have
your phenom, try researching to unlock it. if not, then at least get a quad core to limit your bottleneck issues.
good luck! happy holidays