[Inori]

Regular defrags are a must, as @Skullmeat mentioned. Obviously, make sure your CPU is adequately cooled, your RAM is in the right memory channels (otherwise it might not be getting used optimally, if at all), and your case has good, low-pressure airflow (also prevents dust from building up, so you need to clean less).

I remember reading something on the Arch or XFCE wiki that went along the lines of "disabling any integrated graphics in the system's BIOS can boost performance by forcing the window manager to use only dedicated cards."
Given that it's a firmware/hardware optimization method, I would assume it works on Windows, but I wouldn't put it past Microsoft to fuck that up, too.