There might be several reasons for 3000 MHz RAM running at 2133 MHz. There are a few factors that can cause 3000 MHz RAM to operate at a lower frequency. The motherboard’s BIOS default settings are one frequently cited cause. Read More: https://metadictory.com/optimizing-ram-learning-the-impact-of-3000-mhz-ram-running-at-2133mhz/