That Phenom X4 9150e is very weak.In fact it's the slowest non TLB bugged Phenom of the original series not to be confused with the much improved and faster Phenom II's.For gaming your old Athlon X2 5000+ is better but for applications that can use the extra cores the Phenom X4 9150e would be better.
The newer Athlon II's like the X3's or X4's or any of the Phenom II series would outperform both of those CPU's easily.Even some Athlon II X2's would do better.
Your motherboard would be capable of using these more modern CPU's.http://support.asus.com/cpusupport/cpusupport.aspx?SLanguage=en-us&model=M4A785-M&product=1&os=30
As for an example let's compare a budget (cheap) newer Athlon II X3 450 to an old Athlon II 5000+ CPU.http://www.anandtech.com/bench/Product/33?vs=189
I suggest if you game to pick up at least a Athlon II X3 CPU instead and not use those older CPU's unless you don't want to spend any more money.
However if you play older games those CPU's might be satisfactory for your needs.
Not quite up to par for modern gaming though.