For the money, free, you are good. Intel tick-tocks really haven't done much overall until you get to CoffeeLake, where the additional 2 cores can make a sizable difference in multitasking things like gaming and streaming.
So it'll only be a move to something like an i5-8400 or Ryzen R5 2600 and DDR4 ram where you'll really notice any performance differences. Real life terms are not the same as synthetic benchmarks, a real person can't tell the difference between 50fps and 60fps yet to some, that's a huge leap.
I'm still puttering around on an i7-3770K and gtx970 and everything I play on 1080p/60Hz is buttery smooth, no hiccups or tearing or stuttering. If I've lost a little in details in some, oh well, don't notice.
You...