MeasureStringAdd.ps1

# download and install https://github.com/IISResetMe/MeasureScript/tree/master/src
Import-Module MeasureScript 

Measure-Script -ScriptBlock {# use a stopwatch to measure performance
$stopwatch = [System.Diagnostics.Stopwatch]::StartNew()

# create a StringBuilder
$text = ""

# appending a string often 
# using foreach and avoiding the pipeline
foreach($_ in (1..10000))
{
    # replace operator += with AddLine():
    $text += "working on $_`r`n"
}} |Tee-Object -Variable results

# Copy $results[11].TimeLine.TimeSpans to a file and feed to a line graph plotter (I just pasted it into Excel)