Generally, you'll in no way shape or form tap out that CPU with a R9-290. The severity of the impact of that CPU on the GPU would be zero, or effectively zero (it WILL definitely depend on the game) - particularly if you're willing to overclock it just a smidgeon.
Not true. You'd get better performance in games with an Intel I5 than the fx6300. However, it would be much cheaper to replace the fx6300 with a better cpu, than spending money on an Intel I5, and having to replace the video card later. Last I heard, AMD was still going to use socket AM3+ for their next Cpu's, so getting a fx6300 and a 990fx(or 970) chipset motherboard isn't a bad decision.
Not true. You'd get better performance in games with an Intel I5 than the fx6300.
That might be true for SOME games (and imo it is certainly UNTRUE for ALL games). But how much would it be? The FX 6300 (@3.5 GHz) is about the same speed as a i5 750 (@2.4 GHz), so really which games in particular do you think would really benefit from a faster CPU? For
example, if you're wanting to play last-gen console ports at high resolutions, this combination will be adequate.
Not true. You'd get better performance in games with an Intel I5 than the fx6300
Why stop at a measly i5, just get a i7-4960x and it gives you better performance.
See how that works. He's asking about whether it's better to allocate more budget to the GPU or the CPU. The general logic is give more money to the GPU and ensure the CPU is just good enough to do what you gotta do. The fx-63xx is really cheap for it's performance level, which leaves a bigger budget for to nab a good GPU. You won't be bottlenecked in most situations as your not buying dual titans or anything. Something like a 760 or 770 pairs really well with a fx6300.