I would honestly get the 4790k if you're looking for great performance and you still save more money. I personally have an overpriced i7 5820K (X99 Chipset) overclocked at 4.7 GHz, but the 4790k literally gets close to the same performance as my 5820K

OklahomaCityThunder wrote the 4790k literally gets close to the same performance as my 5820K

No, it does not. I have a 4790k, at 4.7GHz. If you want, compare with mine. We can compare clock for clock and stock vs stock if you wish. The 4790k is better than the 5820k in gaming, where less than 6C/12T are being used. The 5820k is better when all cores/threads are being utilised. This is because the 4790k has superior per core performance, whereas the 5820k has 2 more cores, and 4 more threads. The 5820k isn't over-priced at all IMO, it's actually incredibly well priced. The 6800k, 5930k/6850k, and 6950x are over-priced. Even the 5960x/6900k should be cheaper now. The 5820k is literally the only X99 CPU I'd consider not over-priced lol.

OP- 6700 makes no sense. You'd need a new motherboard and RAM, and that's just not logical. The 4790k also does not make sense, however, since you don't have a Z87/Z97 chipset motherboard and can't overclock anyway, so an unlocked CPU is pointless. An i7-4770/4790(non k) would be more logical, but not the best purchase IMO. You can pick up a Xeon E3-1230 V3 or E3-1231 V3 which will perform pretty much the exact same as a 4770 or 4790(respectively), but the Xeon's don't have an iGPU. iGPU is not necessary anyway, since you have a discrete GPU.