Your largest upgrade is going to come from newer architecture. Both of the CPUs you mentioned are Phenom 1 series CPUs. That series had its issues and didn't have great performance (not to mention terrible Overclocking potential).
If your friend has one of the motherboards on this CPU support list:
Click Here Then it looks as the though there is a bios that supports some Phenom 2 based Cpus.
For gaming and price / performance (and going solely by the aforementioned .pdf) , the Phenom x3 720 is a great choice. Add the capability to Overclock to 3.3-3.4ghz on just about any platform, and its an EXCELLENT processor for anything you'd really wanna do with it.
(XFX limits their support site to registered users only, so bios updates and board revisions i don't have quick access to.)
But keep what I said in mind, Go with a Phenom II based CPU if upgrading, anything else wont feel like an upgrade. (speaking from experience here, I've upgraded three processors now (in this particular system), Athlon64 3800+ to, Athlon64 x2 5000+ to, what i have now is a Phenom II x4 940. (all processors where overclocked to 3.5ghz)
Remember AMD key architectures, from oldest to newest:
athlon64, Phenom, to now Phenom II.
The naming gets confusing however. For example: the athlon64 x2 7850 is based on the phenom 1. Little trick to help is anything with a 4 number model number (eg: Phenom
9500 or athlon64 x2
7850) is based on the first Phenom.
On the other hand, anything based on the newer(est) Phenom 2 will have only 3 number model numbers (eg: Phenom x4
940 or Phenom x3
720)
Anything with a "+" at the end of it is the now very old Athlon64 tech. (eg: athlon64 3800
+)
oh, and if your worried about the 95w board not OverClocking well... I have two 750a chipset based boards with 95w max support (both with Athlon II x3 440s) overclocked to 3.5 with ease.
I know Im not the greatest at conveying my thoughts via text, but i hope its not too confusing.