I'm looking to upgrade my CPU and would highly appreciate some advise on choosing the best available gaming CPU that will fit in my ECS C51PVGM-GB mobo
You would be best off getting this CPU. It's slower than the X2 6400+ which would be faster out of the box, but the Brisbane chip will run cooler and be less power hungry. If you want the fastest available though, I would recommend this CPU.
No GPU draws 425W from the +12V rail. The required amperage number given on most video card boxes is for an entire system. You should be fine since it seems you have at least 30+ amps on the +12V rail(s).
Even though it's a phenom chip, it's listed as being AM2+ which is physically the same pin out as the AM2. Wouldn't there be a chance of it working?
Is it the FSB? I'm having problems finding info on the mb and this chip. AMD lists the 7750 but not the 7750 BE, I have a feeling that the FSB is the problem.
I've found some other references to using an AM2+ chip in an AM2 board, but the boards were Asus. (I'd link but my post count is too low)
Sorry to be a pain, I wish the 6400+ was available here, I'd just get it...