Question CPU and GPU acting in a weird way when playing demanding games

[Kenan2000]

So i have a pretty crappy by current standards computer for gaming:
CPU - Intel Core i7 4850HQ @ 2.30GHz
GPU - Nvidia Geforce 2GB GT 750m
RAM - 16.0 GB Dual-Channel DDR3 @ 798MHz
It's a Mac with Bootcamped Windows 10 on it, so here's the catch:

For example, i played many demanding games (Nvidia GTX 640 minimum system requirement, just so you know) just fine before but now something terribly wrong is happening, take Far Cry 4:
It always ran smoothly without lag spikes at constant temperature, now this happens: CPU and GPU get to higher 70s, maybe 80 but not higher - game runs smoothly then after 5 minutes of playing BOTH CPU and GPU get to lower 70s and game starts to stutter and FPS rate drops significantly, why is this happening?

Is there any way to make CPU and GPU work at constant rate without this idiotic fluctuation?
I'm sorry, i'm just really pissed off regarding this, i understand that my computer is getting weaker but this stuff did not happen before.

 

[gustavo302]

I'm having this same issue with a bit better gear. Probably is the ram. I have a dd3 as well 800mhz. I think in buying a ddr4 but for that its need a new motherboard and cpu....
https://www.amazon.com/Kingston-Tec...s&qid=1558896031&s=gateway&sr=8-1-spons&psc=1
This one looks to be a good ram.

Ram could be the issue because the ram feeds the cpu and probably the cpu is faster than the ram, so the cpu slows down with the gpu too.

 

[Kenan2000]

I'm having this same issue with a bit better gear. Probably is the ram. I have a dd3 as well 800mhz. I think in buying a ddr4 but for that its need a new motherboard and cpu....
https://www.amazon.com/Kingston-Tec...s&qid=1558896031&s=gateway&sr=8-1-spons&psc=1
This one looks to be a good ram.


Ram could be the issue because the ram feeds the cpu and probably the cpu is faster than the ram, so the cpu slows down with the gpu too.

Thanks for your reply, i'll bring the PC to the appropriate master, but something tells me that this has to do with CPU and GPU overheating, because game has amazing FPS at both 70 degrees AND 86-90 degrees, then temperature drops and stuttering occurs, it really seems like throttling due to overheating.

I guess that i need to check the fans, apply a new paste, etc first.It REALLY seems like an overheating problem.