In JDK-8369191 we fixed some ergonomics documentation to

"The VM considers machines as server-class if the VM detects two or more processors and a heap size larger or equal to 1792 MB."

However there is another error - it should read:

The VM considers machines as server-class if the VM detects two or more processors and physical memory larger or equal to 1792 MB.

Note the change of "a heap size" to "physical memory".