PCMark 10 displays the value supplied by the system, but the value for the vast majority of integrated GPUs is actually not true. There is no dedicated VRAM present on these systems at all.
Integrated GPUs have 0 MB of dedicated video RAM. They use shared main RAM instead. However, hardware vendors have configured these systems to say that they have dedicated video RAM—usually a value between 32 MB and 256 MB—to improve compatibility with legacy applications that refuse to start if there is no dedicated VRAM. The value can vary between systems even with the same integrated GPU as the value is set by the BIOS. Contact the vendor of your integrated GPU for more details.
The only exceptions are integrated GPUs in the Intel Iris Pro and Radeon Vega M series that feature real dedicated VRAM. PCMark 10 shows the correct dedicated VRAM in these cases.