Thank you for the motherboard picture. I opened the chassis and the top/middle slots were obscured by the GPU, but the bottom one was clearly available. Now I ordered a 3rd gen
WD Blue SN570 2TB drive that was on sale and had great reviews. The motherboard can’t handle 4th gen unfortunately. When I get it I will install the FS on it and do the test above again to see what effect it has on gameplay apart from faster loading times.