While I agree that seeing a full resolution test is also beneficial these 1080p tests do actually provide some very useful info for us by isolating the cpu from interference from any graphics bottlenecks. A realistic full resolution use case will usually be gpu limited and mask the true performance of the cpu.
The most important bits the 1080p tests show are the 1% lows in fps and more importantly the difference between max fps and the 1% low for each cpu. That right there is your smoothness metric. If the gulf between max fps and the 1% is huge you can expect stutters in the sim to be pretty severe, regardless of resolution. The closer they are together the more responsive the cpu will be to sudden scenery loading demands and the smoother your flights will be.
If you run the sim with any kind of fps lock (vsync on or MR in VR) the 1080p charts give a direct read on how much of an unexpected hit each processor can absorb per frame in a worst case scenario before stuttering (think approaching and loading in big addon airports etc).
This is shown nicely in the difference between the 13900k and 5800 X3D. The X3D is a remarkable processor but it isn’t actually that strong under the hood. Its performance comes from cache hits. If those are steady and the demands on the cpu are moderate it really flies, but when it gets hit with a really big demand and a ton of cache misses then it can fall pretty hard due to its lower clock speed and weaker IPC. Stutter resilience and recovery has typically been an intel strong suit due to their generally higher clock speeds.
The 13900k’s power demands though… oy. 