Red_The_Saviour

GPU isnt helping, but it should not be that bad on that GPU with a better CPU.

New Ryzen CPUs soon, in case you haven't been keeping up to date. Worth waiting if you can.

Correct.  3.2ghz would be a nice place to put it if it does not need extra voltage or other tweaks.
 
Games "recommended specs" are just the minimum that they officially support.  You may need to reduce quality settings, and the game may not be smooth enough for you to be as competitive as people with newer rigs, but it should run.

If I were you, I keep it as it is. you dont want to stress a 7yrs old pc like that, keep it cool and functionable .+/- 300mhz wont make any help
...unless you want an excuse to buy new pc...
 
the game shall still run on 750, then you could tell how much the cpu is left behind.
 

they aren't working on a prebuilt's motherboard on the start.

You have to be using a motherboard that allows you to set every CPU/Memory related voltage and timing manually to get much further.  With your system you are limited to stock vcore and stock memory timings.

Not happening.
 
You can, at most, boost the FSB a little with SoftFSB or some similar tool.  This would get you maybe into the ~3ghz range.

How did you discern this exactly?
An i5 750 at 3.7GHz is going to struggle as much as it does at 3.2 in my opinion, a mere quad core and a very old one at that, the .5 GHz increase is about a 15% boost and you'll need a lot more than that for playable battlefield.

4.0 GHz? And what motherboard and cooler is this being attempted with?

Monitor temps, don't go over ~1.5v, and get a fat cooler (air or water does NOT matter).  Not sure what temps are recommended for that CPU, but 70c-80c should be about as high as you want to see.
 
Just start raising the FSB in 10-20mhz increments to start.  Maybe set your memory timings manually and reduce its target speed so you are not overclocking the RAM too far.  Check for stability at each step.

You're gonna need to tell us a lot more to determine if your plan is even feasible.

you basically need "adequate" cooling & adjust core voltage for overclocking.
but a i5 750 is just a 4 core cpu, you will hardly see a difference in those games no matter what clocks.