Can you tell us what particular issues you are having.
Can you also answer the above for us.
The EVGA is only entry level and wouldn't be good enough for a gaming rig but it is adequate for your hardware.
The major update on 12/12/2017 was effectively a clean install of Windows but without removing your personal files and settings, some apps and drivers may need to be reinstalled though.
No OCing or BIOS changes having been made info acknowledged, what I would do though is restore the MBs default factory settings in the BIOS, just in case there is a bad setting, this is a standard step and one of the first that should be done when troubleshooting hardware, restart the computer while tapping the Del key to get you into the BIOS, navigate the BIOS until you find the Load Setup Defaults option, select it then save and exit by pressing the F10 key.
There is nothing that you can do about the RAM speed as neither speeds that you have are capable of running at 1866MHz, go back to Speccy and you will be able to see for yourself that your 1600MHz Crucial RAM is only running at 669MHz, this is because any RAM in a motherboard can and will only run at the speed of the slowest RAM, in this instance your 1333MHz Samsung RAM.
25% RAM usage is still high when you have 12GB of RAM onboard.
What sort of noise was the CPU fan making, if rumbling etc it suggests a problem but if only running at high speed something is causing it to do this and the CPU fan is doing it`s job.
The problems with my wife's computer are Win 10 related. No sound from the speakers(worked fine a week ago with either the monitor speakers or the externals) and unable to get Admin privileges. It stops me from going into the device manager and checking the drivers. Seriously thinking about doing a system refresh.
To avoid confusion and any possible mishaps only one computer and problem per thread, the same rules apply on all reputable forums and you will need to start a second thread for the other computer as and when it is appropriate.