I was looking at it and it can be made more efficient if you assign the ‘get-eventlog’ to a variable and query that each time rather than using ‘get-eventlog’ three times.

From line 161 …
foreach ($domaincontroller in $domaincontrollers){
$x = Get-EventLog -LogName ‘Security’ -ComputerName $domaincontroller -After ((Get-Date).AddDays(-1))

This will find all event logs in the last day using the ‘-After’ option of hte Get-EvenLog cmdlet.

You can then use this variable to find the events you are after, not needing the isWithin function as we have the timeframe already defined …

$MyReport += Get-HTMLTable ($x | Where-Object {$_.EventID -eq “636″ -or $_.EventID -eq “4732″} | select TimeGenerated,Message )

By doing this, we only run ‘Get-Evenlog’ once against each DC instead of 6 times and so the job is much quicker.

I hope you find this helpful

Unfortunately I`m having some problems with the PoshCode.org uploading (http://powershellcommunity.org/tabid/54/afv/topic/aff/9/aft/4304/Default.aspx).

Until the problem is resolved the script are available from this link:
http://80.203.207.194/temp/Get-ADGroupModificationsReport.txt

I`ve also updated the link in the blog-post.

–Jan Egil–