Craggzoid

Why not mix it up? So you get the constant airflow from fixed fans then the higher airflow form pwm fans when you need it?
 
So have 
Front 2x pwm 1x fixed
Top 2x fixed
Back 1x own
 
As for what is best, you just have to test and see if it makes any difference. I can't remember if having positive pressure (more in that out) or negative was better. 

If it’s still the same FPS then you’re still bottlenecked. 
 
...which is totally normal because it looks like your processor is being maxed out. Games don’t utilize every possible thread available, especially ones as old as GTA V which is why even though the game is maxing out its threads, your processor has more than the game can use and only shows 50% usage.
 
Your GPU only jumped its resource usage because MSAA is a massive resource hog.

I have the carbon wifi and have zero issues with it. Left my 5800x at stock so far and temps are perfectly fine, XMP runs without issue on my Corsair 3600 CL18 kit. Wifi and bluetooth on this are great, I'm glad I paid the extra as my Sony BT headphones pair instantly and sound much better vs my old usb adapter. I hardly use my speakers so if you're just after good audio Tomahawk may be better. 

Looking at your posts I'd recommend this board (I haven't used any others so can't compare)
Loads of fan headers
Loads of USB
XMP works fine
Wifi is a nice to have as you can't move your PC around without worrying about ethernet, this also have 2.5Gig LAN, not that you'll ever use that bandwidth. 

I can only think having the distance scaling so high is causing a bottleneck somewhere. Try this and see if it helps. 
 
Disable V-sync
Extended distance scaling off
Distancing scaling, population pull them back a few clicks
Turn MSAA to 4x 
 
I've locked my FPS to 61 in GTA, your FPS seems OK but the low usage doesn't. 
 

Tech Jesus covers the input output very well in this video. 
 
https://youtu.be/BbGomv195sk

I own a 2500k (running at 4.5) 16GB ram and a 970. I play all my games at 1080p on Ultra or High, buttery smooth performance in 99% of games. Looking at your list of games I get the following
CSGO: Max everything runs at silly FPS, will not be a problem at all
BF4/BF1 Beta: Mix of High and Ultra runs around 80 fps, some slight slowdown in very busy scenes but no issues at all in playability.
DayZ: Havent played for ages but game was very playable on High settings (you may need to tweak some of the settings to your preference), but you will have no issues.
GTA: Game is quite CPU dependant but you will be fine playing on High
 
There are some good youtube videos showing comparisons between old and new 
 
This is i7 comparison but you can see how the newer cpu scales
 
 
At the end of the day it all depends on your budget, if you can get the new CPU, if not the 2500k (if you overclock) will last you at least a year and a half, depending on what you play and the settings. 

I own a 2500k (running at 4.5) 16GB ram and a 970. I play all my games at 1080p on Ultra or High, buttery smooth performance in 99% of games. Looking at your list of games I get the following
CSGO: Max everything runs at silly FPS, will not be a problem at all
BF4/BF1 Beta: Mix of High and Ultra runs around 80 fps, some slight slowdown in very busy scenes but no issues at all in playability.
DayZ: Havent played for ages but game was very playable on High settings (you may need to tweak some of the settings to your preference), but you will have no issues.
GTA: Game is quite CPU dependant but you will be fine playing on High
 
There are some good youtube videos showing comparisons between old and new 
 
This is i7 comparison but you can see how the newer cpu scales
 
 
At the end of the day it all depends on your budget, if you can get the new CPU, if not the 2500k (if you overclock) will last you at least a year and a half, depending on what you play and the settings.