This message was posted on behalf of Intel Corporation
I understand that you have an issue with the reported dedicated video memory.
Regarding this, I would like to start by saying that there is no way to preset this to a specific value, you can only limit the maximum memory that it can take. You will see this option usually in BIOS and you will have 3 options: 128 MB, 256 MB and maximum DVMT. You can find other values like 512 MB, but this depends on the motherboard manufacturer and the amount of RAM installed on your computer.
If this amount is changeable then it can be changed in the BIOS, in this case, for more details and help in doing so, I would recommend you to get in contact with either your system manufacturer, or the motherboard manufacturer. I would also like to know, aside from the confusion, are you experiencing any performance problem or something similar?
I hope this helps.
I would add that the Intel HD Graphics driver will allocate the memory required (up to 50% of available memory space). You really only need to worry about this if you have an older (non-compliant) or recent (but buggy) game that stupidly thinks it needs the always-dedicated memory to be a certain minimum size. If nothing is actually complaining or refusing to run, then you do not need to worry about it.