The
B450M PRO-VDH MAX
specifications say:
- 4 x DDR4 memory slots, support up to 128GB *ComboPI 1.0.0.3-based and above BIOS are required.1
- Supports 1866/ 2133/ 2400/ 2667Mhz (by JEDEC)
- For AMD Ryzen Gen3 (R5/R7/R9)
Supports 2667/ 2800/ 2933/ 3000/ 3066/ 3200/ 3466/ 3733/ 3866 MHz (by A-XMP OC MODE)
- For AMD Other Processors
Supports 2667/ 2800/ 2933/ 3000/ 3066/ 3200/ 3466 MHz (by A-XMP OC MODE)
Since your CPU
MD Ryzen™ 5 2400G with Radeon RX Vega 11 Graphics,
is Gen2, the most it can do is 2667Mhz.
The tech-specs of your CPU say:
SPD Speed 2133MHz
Speed Rating PC4-24000 (3000MHz)
"SPD Speed" means
Serial presence detect, which means:
In computing, serial presence detect (SPD) is a standardized way to automatically access information about a memory module.
In other words, this is the information that the BIOS will see and which
it will communicate to the operating system.
The only way to override it, is to either manually choose an XMP profile,
or to modify the hardware parameters.
Modifying these parameters is a complex procedure.
If you follow it, expect boot failures.
Some understanding of the complexity involved you may find in the thread
For Those Who Don't Know What SPD memory speed is for.
I don't really recommend going this way.
For your problem of Hardware reserved memory, this is memory
is generally a part of shared VRAM (graphics memory).
However, there is no explanation as to why when jacking up the
RAM frequency you find yourself with less RAM than before.
The only explanation I can think of is that one of your RAM sticks
is faulty and cannot work correctly under the XMP setting that you chose.
You may try to insert the sticks one-at-a-time under this XMP setting,
to see if both function correctly.