SeniorTaquito
I think it would be hard to pin point a specific cause of eye strain from a new build PC, because everything is new (and untested), and there could be multiple causes of eye strain in there. Windows 10 is known to cause eye strain. Graphics drivers, dithering, PWM in monitor etc are all potential causes of eye strain.
The best (and in my opinion, the only way) to know if one particular component is the cause of the eye strain is to start from "zero eye strain starting point". i.e. The setup is completely eye-strain free, and you can use the setup (PC/laptop) for hours and hours without any eye strain whatsoever. With this starting point, you change just one thing, for example, you installed a new graphics card (the rest is exactly the same), and it causes eye strain. When you remove that one new item (in this example, the new graphic card), the eye strain is gone. This, imho, is the best way to isolate and identify what specific item/component is the cause of the eye strain.