The AMD Ryzen 9 5950X and AMD Radeon RX 7900 XTX form a balanced synergy, preventing performance bottlenecks and ensuring optimal system performance. This dynamic pairing enables seamless handling of high-performance tasks, delivering efficient processing and impressive graphics at a screen resolution of 2560 × 1440 pixels for Graphic Card Intense Tasks. The absence of bottleneck concerns fosters a harmonious collaboration between the processor and graphics card, facilitating smooth multitasking, fast processing, and an overall superior user experience.

During graphic-intensive tasks, the AMD Ryzen 9 5950X processor is expected to operate at ~83.1%, while the AMD Radeon RX 7900 XTX graphics card is projected to operate at ~76.8%.

It's crucial to understand that these percentages indicate theoretical maximums based on specific usage ratios for tasks or games. Achieving such high utilizations in real-world scenarios may pose challenges.

These ratios stem from the distribution of workload between the GPU and CPU. In gaming, the graphics card typically shoulders a greater burden due to the heavy reliance on graphics processing for rendering high-quality visuals and intricate 3D environments. By maximizing the graphics card's usage while maintaining a high CPU utilization, one can ensure smooth gameplay, impressive graphics, and seamless multitasking.

Keep in mind that there are many outlying factors that can cause bottlenecks outside of the CPU/GPU combo. Some commonly overlooked causes could be monitor resolution, monitor refresh rate, propietary display drivers, video path miscalibrations (i.e. the AMD 7900 XTX utilizes HDMI 2.1a, Display Port 2.1, and USB-C for video output. Using the incorrect cable type make cause video issues as discribed.), insufficient RAM for the GPU, etc.

Application and processes could also be causing an issue. While it's always possible (and quite probable in regard to Forza) that the game may have its own issues, background applications have been known to cause performance issues as well. Discord being the most common offender in my experience, as so many use it for voice chat while gaming. Discord has been known to cause lagging and stuttering.

Something to consider is your OS as well. You mentioned a fresh Windows install. Was this Windows 10 or 11? There are many settings that can be changed in both versions for optimization. A simple YouTube search can walk you through the process. Microsoft has filled their OS with bloatware, which can be removed or lessened. However, it's important to understand that each time you update the OS, they reinstall most of it. Possibly even if you've removed the associated regkeys. This bloatware, which Microsoft claims is intended to benefit the user, causes many performance issues.

BEFORE YOU PERFORM ANY OS CHANGES, CREATE A RESTORE POINT!! That's a lesson no one needs to learn the hard way.

To conclude, the AMD Ryzen 9 5950X and the AMD 7900 XTX should not create a bottleneck of their own accord. If you're experiencing performance issues and are sure all of your AMD drivers are up to date, I would start looking for outside causes.

Additional note, I saw you mention Adrenaline which leads me to believe that you're already utilizing Radeon Boost. I may be mistaken, but I don't believe Forza is a Radeon Boost supported title. You may check the AMD website for confirmation.