3DMark Solar Bay measures graphics performance, and it does not have a CPU test.
The Solar Bay graphics test features ray-traced reflections, volumetric lighting, particles, and post-processing effects. The scene consists of three sections, with the ray tracing workload increasing in each section. The second and third sections target an average of 2x and 3x the ray tracing workload of the first section.
The test is built using Vulkan 1.1 and runs at a 2560 × 1440 rendering resolution before scaling the content to the display.
The main role of the CPU in the rendering process is to compose the command lists that the GPU executes. The Solar Bay engine is multi-threaded and divides the work between all logical cores.
If the CPU cannot submit work to the GPU fast enough, it will be the limiting factor in the benchmark, effectively invalidating the result of the Graphics test. Solar Bay requires a multi-core CPU to run at high frame rates.
The exact point at which the benchmark becomes bound by the CPU depends on the configuration of the system.