Hi PentiumCadiz ,
I think that all 512MB. I don't know why you would buy only 512MB when you can buy at least 8GB or even 16 DDR4 2100.
I think that the shared capacity depends of mainboad.
I can tell you that on Asrock z170 Extreme 7+ the max memory that can be shared as dedicated in bios is 1792MB with 16GB DDR4.
But the driver overrides that and on windows 8.1 you have 4096MB and on Windows 10, 8192MB.
This message was posted on behalf of Intel Corporation
This graphics controller uses shared memory. The Intel® HD Graphics 530 has a graphics max dynamic frequency of 1.15GHz, however; the minimum and maximum amount of shared memory for graphics is customized by the computer manufacturers. In most cases they have already configured the system to use the maximum amount of graphics memory that is possible for your particular computer model.