As I understand it, the assertion is that the 1080p FPS is the same as 2k/4k FPS, assuming that you have an infinitely powerful GPU. So the 1080p FPS is your max potential FPS at any resolution with the CPU, and then you need to look at a GPU 2k/4k chart to see how much FPS it can achieve from that target. HWUnboxed also reasons that gamers are not blindly using ultra settings, so in real scenarios people are going to be lowering their settings to try to achieve a specific FPS target anyway. They also mention that lowering ingame settings doesn’t usually affect the CPU FPS benchmark.

So in summary, the 1080p CPU benchmark is the ~highest possible target you can achieve, and then it’s up to your GPU and ingame settings to decide how much of that target you can reach. It’s a little more difficult to grasp and calculate mentally, but it prevents the 2k/4k benchmark data from showing what is effectively misleading “point in time” data that will not be useful if you have a different GPU or ingame settings. This is most clearly demonstrated by re-reviewing older CPUs in the future-proof section and showing that putting massive GPUs on old CPUs puts the FPS benchmarks of all resolutions to roughly the same value - i.e. the CPU doesn’t truly have an effect w/r/t resolution, it’s mainly just the GPU.

One of the main points of this video is that 1080p testing is the only thing you should be looking at for CPU benchmarks (to the point that HWUnboxed is no longer doing 2k/4k testing in the future I think?), and although I was skeptical at first, the future-proof section did finally convince me. The new problem with this line of thinking is that you really need to be cross-referencing a GPU benchmark to figure out what a real world 2k/4k scenario will look like for the CPU you’re interested in.