$VMs = Get-VM | Where-Object { $_.ExtensionData.summary.config.ManagedBy.Type -ne "placeholderVm" }

$result = [System.Collections.ArrayList]@()
ForEach ($VM in $VMs) {
    $Disks = $VM | Get-HardDisk
    $TotalThreads = $Disks.count
    $256GBDisks = ($Disks | where-object CapacityGB -gt 256) 

    $obj = [PSCustomObject]@{
        'ComputerName'      = $VM.Name;
        'NumOfDisks'        = $Disks.count
        'NumOver256GB'      = $256GBDisks.count
        #'NumOf256GBThreads' = $TotalThreads
    }

    #Write-Output $obj
    $null = $result.Add($obj)
}

$result