Hello, well man, I am playing Apex legends and doing some .cad work on my pc. I have my pc since 2013, which I have build by my own and It has some similar parts that I have read in your messages.
Here's my set up:
Asus Z87-K
4670-K
Cooler master Hyper 212 evo
GTX 970 4Gb
8 Gb of RAM (should be at least 16 for these days, 32 would be above avarage)
1 TB, no SSD
And only today I have realised, that all the time until today my 4670-K was bottlenecking my GTX970 by more than 30 procent.
So I decided to overclock it after whole day reading all the guides and forums.
So now, I just have overclocked my old 4670-K to 4.3ghz. Running stable at 1.220V at least for now
I went straight for the 4.3 instead of increasing it by lower steps. I have set the voltage at 1.200. At first it started without crashing, but after loging in and trying to open a few programs, programs just couldn't load. They were opening, but freezing at the loading screen and then crashing. After a few more tries to load at least something, my PC crashed with a blue screen. Then I went for 1.208V, just becouse I saw a guy with very similar kit running at that 1.208 stable. So when I got into my desktop, now I could open programs and it loaded normally. So I've tried to run a game and it crashed as soon as I was in a games lobby, again same blue screen. So I went for a 1.220V, ran a stress test, with witch I got 82 degrees on one of the cores, but it didn't crashed and after that I ran a game without any problems or crashes. So after all I think that's the most I can go for with CM 212 evo cooler. But I still think that 4.4 is reacheable and even more with a better cooler, just every chip is different, some of people barely can get stable 4.2 ghz, but other ones can go 4.6 easy, and some (I believe less than 5proc. of chips) even above 5 Ghz.
I have checked it and there is no bottleneck anymore and I have increased the performance of both, CPU and GPU. So I recommend you going with the overclockable procesor of 4670-K.