I'm running a "890GPA-UD3H" Mobo w/ Phenom II X4 C3 @ Default 3.0Ghz with 8GB of DDR3 GSkill Ram at 1600MHz, 750W Corsair PSU, 500GB HDD plus a 5770 on the side. No plans to overclock w/ the exception of bios flashing a 6950 to perform similar to a 6970 if my CPU can handle it. But I do plan to play games on a 24" 1080P Monitor - 1920 x 1200 resolutions. This is intended as a Gaming PC, however my 5770 is starting to lose ground in terms of performance due to it's age. Currently trying to figure out ALL of my GPU options, which is why I'm trying to find out what my CPU can handle.
Additional info/specs on my Phenom II x4 945 C3 can be found via the link below.
The higher the resolution, the less impact pure CPU clockspeed has, as most of the load is shifted to the GPU. Phenoms are not capable of the framerates at low res that SB CPUS are, but, you should be just fine at your res.
Currently, the 6950 or 560Ti are the potent 'must have' cards in the midrange, trading blows over price vs. performance, varying according to which game and resolution is examined. Both cards are good, however.
instead of thinking about it as a "bottleneck", a term which is way overused, you need to ask yourself two things.
"Is this video card going to give me adequate FPS in the games I play with X quality and resolution settings and give me some room for newer games?"
"Will this CPU give me adequate FPS in the games i play with X quality settings?"
For a 1920x1200 monitor you really want a 6950 or better, but if you want to run something like crysis 2 with dx11 and all options on at that res, regardless of your cpu, you will need a gtx570/6970 or better. At the moment a quad core at 3ghz should play most things with good fps, some games that dont utilise 4 cores would benefit more from more clock speed, in which case you should overclock the CPU. It should take little effort to get that cpu to at least 3.6ghz.