A new rumour states that the MediaTek Dimensity is up to 25% more power-efficient than the Snapdragon 898. Both chipsets are slated to share an identical core configuration (1xCortex-X2 + 3xCortex-A710 + 4xCortex-A510), but the Dimensity 1200 will use an ARM Mali G79 GPU.
https://www.notebookcheck.net/MediaTek-Dimensity-2000-to-feature-an-ARM-Cortex-X2-CPU-core-will-allegedly-perform-on-par-with-the-Snapdragon-898.569330.0.html