Data Mining shared mail box using powershell via com object Performance is really bad.

Question

I was trying to pull a report from multiple shared mail boxes by configuring them in outlook. Everything works fine for me here but the problem is that the below script would need a minimum of 10-14 hours on weekly basis. Can you please comment me on how
can I get more performance? My average mailbox details and my observations are as below:
It would have about 35 sub folders recursively up to 3 levels in Inbox.
It would have ~ 300,000 to 400,000 emails.
I donot know if this can be easily accomplished via EMC Shell but I dont have it either.
And these are configured in Outlook 2013.
The biggest folder has about 60000 emails.
Even plain export without any filter or calculated values in the output is taking the similar time.
I have even tried to use pick folder and manually executed multiple instances (~10) for each folder but the performance was really worst.
-------------------------Script Starts here--------------------------------------
Filter WeeklyReport {If((($_.SentOn -ge ("12/14/2014" -as [datetime])) -and ($_.SentOn -le ("12/20/2014" -as [datetime])))){$_}}
$ReportFileName="~\Desktop\EMail_Export_$(get-date -f yyyy-MM-dd-HH-mm).csv"
function GetSubfolders($Parent) { 
    $folders = $Parent.Folders 
    foreach ($folder in $folders) { 
        $Subfolder = $Parent.Folders.Item($folder.Name) 
        Write-Host ("Started processing"+$folder.Name +" at "+$(Get-Date)+" which has "+$folder.items.Count + " items ") -NoNewLine
        $folder.Items | WeeklyReport | Select-Object -Property SenderEmailType,ConversationTopic,CreationTime,ReceivedTime,Importance,LastModificationTime,Size,Subject,CC,ReceivedByName,ReceivedOnBehalfOfName,SenderName,SentOn,SentOnBehalfOfName,To,SenderEmailAddress,Categories,@{N='FolderName';E={$($folder.Name)}}
| epcsv -Path $ReportFileName -NoTypeInformation -Append
        Write-Host ($(Get-Date))
        GetSubfolders($Subfolder) 
Add-Type -AssemblyName "Microsoft.Office.Interop.Outlook"
$olFolders = "Microsoft.Office.Interop.Outlook.olDefaultFolders" -as [type]
$outlook = New-Object -ComObject outlook.application
$namespace = $outlook.GetNamespace("MAPI")
$MailBox=$namespace.Folders | ?{$_.Name -eq "[email protected]"}
$MailBoxInbox=$MailBox.Folders | ?{$_.Name -eq "Inbox"}
Write-Host ("Started processing Inbox at "+$(Get-Date)+" which has "+$MailBoxInbox.items.Count + " items") -NoNewLine
$MailBoxInbox.Items | WeeklyReport | Select-Object -Property SenderEmailType,ConversationTopic,CreationTime,ReceivedTime,Importance,LastModificationTime,Size,Subject,CC,ReceivedByName,ReceivedOnBehalfOfName,SenderName,SentOn,SentOnBehalfOfName,To,SenderEmailAddress,Categories,@{N='FolderName';E={'Inbox'}}
| epcsv -Path $ReportFileName -NoTypeInformation -Force
Write-Host ($(Get-Date))
GetSubfolders($MailBoxInbox)
$outlook.quit()
-------------------------Script Ends here--------------------------------------
--VenuGopal

Answer 1

Aah, Sorry COM object....
I have observed that for the execution of the below line hardly it is taking 1-2 seconds for processing 50,000 items and it is similar even if we dont apply the filter.
$items=$Folder.Items.Restrict($sFilter)
Just got a doubt and found that the performance issue is not while processing the data but export is taking so much of time. For Example: Execution of the below line starts giving out put on the fly.
$items|Select-Property$props|ft-a
Even Out-File is taking so much of time. So, I think I need to start looking out for string builder or Stream Writer rather using epcsv?
--VenuGopal