Programmatically Uploading a Large Number of Documents to a Library

The problem:

I need to see how well my document library performs when it has more than 5,000 documents. To do that, I need to generate more than 5,000 documents and upload them to the library. It would be nice to do it automatically.

The solution:

I have a simple Aha.docx file. First, I need to copy it 5,000 times. I chose to do it via PowerShell:

$path = "C:\Users\Administrator.TWS\Documents\TestDocs\Aha.docx"
$i = 1
do  { $newPath = "C:\Users\Administrator.TWS\Documents\TestDocs\" + $i + ".docx"; Copy-Item $path $newPath; $i++ }
while ($i -le 5000)

Now my TestDocs folder has the Aha.docx file plus 5,000 other files, and I need to upload them to the Documents library. Here is the corresponding PowerShell script:

$spWeb = Get-SPWeb -Identity https://main.my.server.com/sites/Boris/TheSiteIAmTesting
$spFolder = $spWeb.GetFolder("Documents")
$spFileCollection = $spFolder.Files
$path = "C:\Users\Administrator.TWS\Documents\TestDocs\Aha.docx"
$file = Get-ChildItem $path
$spFileCollection.Add("Documents/Aha.docx",$file.OpenRead(),$false)
#Now, let's copy 5000 other files
$i = 1
do { $path = "C:\Users\Administrator.TWS\Documents\TestDocs\" + $i + ".docx"; $file = Get-ChildItem $path;  $spFileCollection.Add("Documents/" + $i + ".docx",$file.OpenRead(),$false); $i++; }
while ($i -le 5000)

Now the Documents library contains the Aha.docx document plus 5,000 more documents, from 1.docx to 5000.docx.