The CPU is plenty. The problem you have right now, is the case, power supply, and motherboard. The motherboard does not have enough PCIe slots to run quad xfire or even tri xfire. The case you have doesnt have enough of those slots where the rear IO/exhaust of the card is, I forgot what they are called. The PSU cant support power hungry 7970s in quad xfire either. I don't recommend quad xfire since scaling is horrendous. Even nVidia has begun to given up on quad SLI (at least in their advertising/demoes) since they find the scaling to be horrible. At the resolution you are running, tri xfire will be enough. As for the CPU though, dont upgrade from a 3570K to a 4770K. The i5 can handle any game for the next 3-5 years fine. As for the 3930K, that CPU is 2 generations old, and will be refreshed soon. That will be a worthy upgrade since it will gain you better performance due to the extra 2 cores. Plus, the X79 platform is meant for multi GPU configurations.