I'd start with BIOS by doing a CMOS reset, especially if you you've never done one since you originally built it.
Then un-install any motherboard apps or utilities. They are at best buggy, at worst little more than spy-ware reporting back to China on everything you do or install. You don't even need the drivers for LAN or audio since Windows will install compatible ones for you. WiFi may be necessary, but I'd suggest finding the WiFi chipset mfr's driver instead of using whatever the motherboard mfr. provides if you can.
In a command prompt with Admin Rights enter
sfc /scannow and let it find and repair Windows system file corruption.
In the search box type
disk cleanup and clean-up the system disk, usually C: drive. Be sure to also clean up system files. After it's completed repeat
sfc /scannow in a Command prompt.
That fixes most Windows problems, more serious problems can be fixed with a
repair install with in-place upgrade. It's similar to a clean install but it retains all settings, installed applications and games and their settings. If the problem is Windows related and none of the above fix it a clean install may be necessary, and especially so if you moved the system drive from your old computer into the new one without a fresh install.
The problem may not be Windows related but a custom setting you've made. That's where changing your BIOS, application or game settings to full default may help you find which it is.
A common hardware problem with new-builds is cooling. Adequate cross-flow ventilation is important for gaming since the GPU's hot exhaust can recirculate, make the it heat up and lower clocks. Just as bad is it can be drawn in by CPU air coolers and prevent it from being adequately cooled. If the CPU VRM is getting no airflow it will heat up and throttle the CPU to prevent damage. Most of these problems won't show up immediately but after the hardware has heat-soaked sufficiently.
This can be very difficult to solve on tiny SFF builds based on mini-ITX boards. What case do you have? How are case fans set up? What is your CPU cooling arrangement?