Compare-Object works different

Sorry Mr. Snover. I don't grock the way Compare-Object is intented to work.

Or I'm just misinterpreting the examples in http://technet.microsoft.com/en-us/library/ee156812.aspx for a second time.

The first time I was led to think, that Compare-Object is a good basis to produce diffs of text files. It hardly is capable to tell whether they are equal or different.

This time I thought it adequat to determine the processes which where started between two calls of GET-Process.
Well it correctly tells the name of the processes involved, but having a lot of chrome processes
(Chrome Plus to be precise) I do not get the PID of correct chrome process stopped.
And for me a process is it primary it's PID and not it's name.

With a little work around I get Compare-Object to work here as expected.

function Get-ProcessProperty ( )            
{            
    [CmdletBinding()]            
    PARAM(            
        $process = '*',             
        $timestamp = "{0:T}" -f (Get-Date)            
        )            
                
    $hash1 = @{}            
    Get-Process -Name $process | % {            
        $hash2 = @{}            
        #$hash2['Time'] =  $timestamp             
        $hash2['Name'] =  $_.name            
        #$hash2['CPU']  =  $_.CPU            
        #$hash2['PM']   =   "{0,3:f0}" -f ( $_.PM  / 1MB )            
        #$hash2['NPM']  =   "{0,4:f1}" -f ( $_.NPM  / 1KB )            
        #... add further properties above            
        $hash1[($_.Id)] =  $hash2            
    }            
    $hash1            
}            
            
            
$psold = get-ProcessProperty            
            
(            
'\PhysicalDisk(_total)\Current Disk Queue Length',              
'\PhysicalDisk(_total)\Disk Transfers/sec'            
) | Get-Counter -cont -sample 1 |% {            
    $timestamp = "{0:T}" -f $_.Timestamp            
            
    $diskQueue =  ($_.CounterSamples[0]).CookedValue            
    $transfer  =  ($_.CounterSamples[1]).CookedValue             
                
    $msg = "{0}  {1,4:f0} {2,4:f0}" -f $timestamp, $diskQueue, $transfer            
            
    $psnew = get-ProcessProperty            
                
    # Show Processes that started or stopped            
    Compare-Object @($psold.keys) @($psnew.keys) |%{            
        $Id  = $_.inputObject            
        if ($_.Sideindicator -eq '=>')            
        {            
            $Name = ($psnew[$id]).Name            
            "$timestamp Start   $Id $Name"            
        }            
        if ($_.Sideindicator -eq '<=')            
        {            
            $Name = ($psold[$id]).Name            
            "$timestamp         $Id $Name   stop"            
        }            
    }            
    $psold = $psnew            
            
    # the following code is special to a problem on my Windows 7 installation                
    # my problem is, when Current Disk Queue Length > 0, but Disk Transfers/sec 0             
    if ($diskQueue -gt 0 -and  $transfer -eq 0)            
    {            
        $msg            
    }                    
}