I will third the HW monitor and also agree with Sharmouta. The PSU you have may not handle the power needs of your GFX card. The card might be fine with the low end stuff, but if the fan needs to crank up for the intense apps, the PSU could be the culpurt.
If BF4 is installed on a normal HDD, then you are capped to the HDD's speed. The SSD will only play a role if the BF4 data is cached on the SSD or RAM. To get have BF4 run the fastest it would need to be placed on the SSD, but that is most of the SSD probably
Boot into safe mode with networking and run a full Malwarebytes scan and Anti-Virus scan. After that, reboot and try the "sfc /scannow" in an elavated command prompt (Admin rights) and it if still doesn't work I would just reinstall Windows. Just my two cents!