When you refer to 'consumption', if you mean the Disk Usage indicator in the RAM Disk application, it's important to note that when a RAM disk is created, it is initially empty. Hence, zero usage is shown. After you transfer some files to the RAM disk, the Disk Usage gauge should begin to reflect the amount of space being taken by those files.
If, on the other hand, you mean the amount of free RAM that you see in your system after the creation of the RAM disk, this behaviour is different on macOS compared to Windows. On a Mac, memory isn't allocated instantly after creating a RAM disk. This means that the available RAM won't change immediately post-creation. However, as you add files to the RAM disk, you will notice a decrease in the available free RAM.