What are you looking for as "proof" that it's there?
Utilities such as CPU-Z will show the amount of cache on the chip.
Running a benchmark and comparing results can tell you it's working.
The 9800X3D is a single CCD, there's no core parking or cache optimization needed, just plug n play!
Ryzen R7 5700X | B550 Gaming X | 2x16GB G.Skill 3600 | Radeon RX 7900XT
Ryzen R7 5700G | B550 Gaming X | 2x8GB G.Skill 4000 | Radeon Vega 8 IGP
Ryzen R5 5600 | B550 Gaming Edge | 4x8GB G.Skill 3600 | Radeon RX 6800XT