WILL MY CPU BOTTLENECK MY GPU(s)???

If your going to go super serious on gaming and spend 600 bucks on gpu's then at least move to the top of the line I5.

If the wallet allows start working your way up the I7 series.

The 7970 is a 250w card.
If your going to run two of them it might be a good idea to bump that psu to the 1kw area.

Of any GPU, good or bad is to allow the CPU to continue working w/o heavily tasking the CPU for video tasks. Once released from the major video demands and the GPU takes over it allows the CPU more power to do whatever else. Sure there are still video tasks required to be handled by the CPU but these have been overall reduced. It always helps to have a CPU that is on equal par with the GPU as in a good match. but even a poor match isn't going to hurt the results that much unless too much in the extremes.

FYI- Make darn sure you have real good cooling setup for prolonged system uptime and reduce heat stress on components. It does make a difference in the long haul. As well as a very good PSU to handle all the needs. Understand any PSU will deliver it's labeled top wattage for short(peak) periods, thus x85% the value as the real top level of sustained operation as being stable. That too is reduced by heat levels and general uptime be sustained for prolonged periods will succumb to wear&tear.

tada -----Willy