Why can't the computer turn up the memory frequency?

You just press F1 and keep trying as prompted in Figure 1, it may be a warning after the BIOS settings have been changed

If it doesn't work, try to turn on the memory frequency with XMP in BIOSA

If you set it up manually, the timings should be set up in accordance with the timings recommended by the memory manufacturer

This parameter can be found by using the SPD tab in CPU-Z to see the parameters recommended by the memory manufacturer

For example, my DDR4 3000 timings are 16-20-20

It is the same for DDR4 3000.

For example, my timings for DDR4 3000 are 16-20-20