Just the fact that I can now comfortably play Company of Heroes 2 vs not being able to play it at all, is a pretty big deal IMHO. On my overclocked e6300 I could only push into the teens and twenties regardless of resolution. Now I am well over 30's and 40's and that's only because I am GPU limited I think.
yes for some games going from a not so fast "C2D" to a fast "C2Q" can easily make the difference of playing a game from not playing it properly, given the investment, I think it's very easy to recommend, if you already have the rest of the system,
looking at your specs I would be more worried with games not playing well with 4GB, and the 6950 not getting driver updates than the CPU, but obviously this varies from game to game quite a bit, some will be more CPU limited, others GPU
So just how old are you guys willing to go? I ran into a problem back when Flash was still alive before HTML5 took over and my dad's old system couldn't play current(at the time) versions of Flash so He couldn't watch movies or play Facebook games on Linux. I end up building him a new system back in 2014 due to this. The old CPU he didn't have the instruction(s) Flash needed.
Don't remember the CPU but I think was at or before Socket 775. Probably before 775.
I think for decent performance on everyday usage you shouldn't really be looking bellow a fast C2D; but, I have used a few P4s recently, and they run current software, just slowly, even the Northwood from 2002 still supports SSE2 and runs pretty much anything (x86) on Windows 7, maybe you father was using Athlon XP? those lack SSE2 and have far worse compatibility with current software.
