a noticable difference between 2 CPUs?

[NikuSama]

so i am torn, i have a shuttle i found dumpster diving and i really want it to be able to play fortune street reliably, it started out pretty poorly using onboard graphics but i borrowed a card and noticed an immeddiate difference how ever its not enough.
Currently its a Shuttle XPC with 4 gigs of Corsair XMS2, a GeForce 240 with 1 gb of ddr5 (which is odd for that card) and a Athlon X2 240
Now i am wondering will i notice much improvment going from the...
Athlon II X2 240:
http://products.amd.com/en-us/DesktopCPU...e&f12=True
to
Phenom II X3 720 BE
http://products.amd.com/en-us/DesktopCPU...e&f12=True
no bios options to overclock in this tiny thing and from what i have read dolphin doesent utilize more than 2 cores, hence my question. Its going to come down to what is faster clock for clock if you ran them both with the same ammount of cores.

[ExtremeDude2]

It will be slightly faster due to the extra core/better architecture

[DefenderX]

But those CPUs are still too slow for more demanding games which need LLE (e.g SMG1/2). This games need a Core i5-3570k @ 4.2GHz to run @ fullspeed. (If VBeam trick is used, stock speed may be enough)

[NaturalViolence]

a GeForce 240 with 1 gb of ddr5 (which is odd for that card)

GDDR5, not DDR5. DDR5 does not exist yet and will probably not exist until around 2020.

Like extreme said expect a small bump in performance. Enough to make it worth it if it's free but if you're paying for this upgrade than I would probably wait to upgrade to something more significant.