Upgrade to Q9400, worth it?

[Jovin5]

Which one is more worth it??
My budget is around $120 for now, i've plan for upgrading my PC.
But get confused with this New or 2nd Hand Built, the New Built make
me must buy entirely new RAM and save more money for it. But with
the 2nd Hand Built isn't, my DDR2 RAM still can be used.
My goal is for a better gaming exprience, specially for GTA V.
Which one is better?
Any suggestion?

My PC:
Intel Pentium E5300 @3.2Ghz (O.C)
Asus P5GC-MX/1333
V-Gen 2Gb DDR2 PC6400
Kingstone 2Gb DDR2 PC6400
Digital Alliance GT 630 2Gb DDR3 128bit
PSU Digital Alliance Bullet 400W

"Price according to my country prices"
New Built
Asus H81M-E $61
G3220 $45
Visipro 4GB DDR3 $25

2nd hand Built
Asus P5Q $28
Q9400 $40

 

[Tradesman1]

The Q9400 would be an improvement over what you have