[Discussion] Is it worth it to upgrade the i2500k for streaming?

Hey guys! I built my current rig about four years ago and have upgraded the video card once (560->770), and overclocked it to 4.5 GHz. I think it runs all the games I really play (League, CS:GO, FO4, Osu!) pretty cleanly, with some minor issues but for a four year old system it's pretty consistent. I was curious, since I'm really wanting to stream, if it would be a good idea to upgrade my PC soon (yeah I just watched the video recently but it had nothing to do with streaming, just game performance).

Current Build:

i5 2500k @4.5 GHz

Gigabyte GA-Z68P-DS3

Thermaltake Water 3.0

Crucial 1600MHz 4GB DDR3 RAM (x2)

MSI Afterburner GTX 770 2GB

ASUS VG248QE 144HZ Monitor

I was looking to upgrade to an i7 4790 and the rest of my rig. (build here) How much of an increase in performance would I see while streaming? Currently I see a noticeable drop in FPS while streaming (since I play a lot of CSGO I want to keep it at 120+ FPS, and I drop to about 70-80 while streaming at 720@30). I'm curious if I should wait for the next iteration of CPUs or upgrade my machine within the year. Thanks!