The 3DMark Fire Strike Ultra Physics Test benchmarks CPU performance by running physics simulations on the CPU. The GPU load is kept as low as possible to ensure that only the CPU is stressed. The Bullet Open Source Physics Library is used as the physics library for the test.  

The test has 32 simulated worlds. One thread per available logical CPU core is used to run simulations. All physics are computed on CPU with soft body vertex data updated to GPU each frame.