TheoTenek :
Please i need to know
can i put 2400mhz ram on B250M-DS3H
Yes, ... you can !
But it will be run with DDR4 2400 (1200 MHz) only with a Intel Kaby Lake CPU,
like the Pentium G4560 (2C / 4T) Model - for example.
With the Skylake CPU Generation are only DDR4 2133 ( 1066 MHz) possible,
even when you enable the XMP 2.0 Profil (DDR4 2400) in the UEFI / BIOS.
However, you can also reduce the Timings of the DDR4 memory,
if you select the manual RAM settings there.
My 2x 8GB (16GB) DDR4 2400 Crucial Ballistix Sport LT (white) Kit
with CL16-16-16-39 / 2T @ 1.20 Volt over XMP 2.0 Profil,
run manually also with CL13-13-13-36 / 2T @ 1.30 Volt
without any problem.