Results for integer and array comparison seem understandable. It does not appear to be comparing the reference (address) of the object. Is it actually comparing the content?

PS C:> $Int1 = 1
PS C:> $Int2 = 1
PS C:> $Int3 = 99
PS C:> $null -eq (Compare-Object -ReferenceObject $Int1 -DifferenceObject $Int2)
True
PS C:> $null -eq (Compare-Object -ReferenceObject $Int1 -DifferenceObject $Int3)
False
PS C:> $Array1 = @(1, 2, 3)
PS C:> $Array2 = @(1, 2, 3)
PS C:> $Array3 = @(1, 2, 99)
PS C:> $null -eq (Compare-Object -ReferenceObject $Array1 -DifferenceObject $Array2)
True
PS C:> $null -eq (Compare-Object -ReferenceObject $Array1 -DifferenceObject $Array3)
False

However, comparison of hashes and pscustomobjects does not appear to work the same way. Why are these all comparing as identical?

PS C:> #How can I compare the contents of the objects?
PS C:> $Hash1 = @{a=1;b=2}
PS C:> $Hash2 = @{a=1;b=2}
PS C:> $Hash3 = @{a=1;b=99}
PS C:> $null -eq (Compare-Object -ReferenceObject $Hash1 -DifferenceObject $Hash2)
True
PS C:> $null -eq (Compare-Object -ReferenceObject $Hash1 -DifferenceObject $Hash3)
True
PS C:>
PS C:> $Obj1 = [PSCustomObject]@{Name = "Sam"; Weight = 145}
PS C:> $Obj2 = [PSCustomObject]@{Name = "Sam"; Weight = 145}
PS C:> $Obj3 = [PSCustomObject]@{Name = "Sam"; Weight = 199}
PS C:> $null -eq (Compare-Object -ReferenceObject $Obj1 -DifferenceObject $Obj2)
True
PS C:> $null -eq (Compare-Object -ReferenceObject $Obj1 -DifferenceObject $Obj3)
True