response to https://communary.wordpress.com/2015/12/13/observations-on-writing-to-screen-and-file-in-powershell/

overheadtest_alittletuned.ps1

$iterations = 10000
$saveFile = 'C:\Users\heman\Desktop\OverheadTests\results.txt'

$m1Description = 'Refence: Only doing calculations'
Write-Host 'Starting Measurement 1'
$m1 = Measure-Command {
    1..100 | ForEach-Object {
        $_ + ($_ * $_)
    }
}

$m2Description = 'Using Write-Host to output result of calculation to the host'
Write-Host 'Starting Measurement 2'
$m2 = Measure-Command {
    1..$iterations | ForEach-Object {
        Write-Host "Result of calculation: $($_ + ($_ * $_))"
    }
}

$m3Description = 'Using Write-Output to output result of calculation'
Write-Host 'Starting Measurement 3'
$m3 = Measure-Command {
    1..$iterations | ForEach-Object {
        Write-Output "Result of calculation: $($_ + ($_ * $_))"
    }
}

$m4Description = 'Saving result of calculation to an Array'
Write-Host 'Starting Measurement 4'
$m4 = Measure-Command {
    $result = @()
    1..$iterations | ForEach-Object {
        $result += $_ + ($_ * $_)
    }
}

$m5Description = 'Saving result of calculation to an ArrayList'
Write-Host 'Starting Measurement 5'
$m5 = Measure-Command {
    $resultAL = New-Object System.Collections.ArrayList
    1..$iterations | ForEach-Object {
        [void]$resultAL.Add(($_ + ($_ * $_)))
    }
}

$m6Description = 'Using Write-Progress to output result of calculation'
Write-Host 'Starting Measurement 6'
$count = 0
$m6 = Measure-Command {
    $sw = [System.Diagnostics.Stopwatch]::StartNew()
    1..$iterations | ForEach-Object {
        $count++
        if ($sw.Elapsed.TotalMilliseconds -ge 500){
            Write-Progress -Activity 'Processing' -CurrentOperation "Result: $($_ + ($_ * $_))" -PercentComplete (($count / $iterations * 100))
            $sw.Reset();
            $sw.Start();
        }
    }
}

$m7Description = 'Save result of calculation to file, write per iteration'
Write-Host 'Starting Measurement 7'
$m7 = Measure-Command {
    1..$iterations | ForEach-Object {
        $result = $_ + ($_ * $_)
        $result | Out-File -FilePath $saveFile -Append
    }
}
Remove-Item -Path $saveFile -Force

$m8Description = 'Save result of calculation to file, write when done (using ArrayList to store results)'
Write-Host 'Starting Measurement 8'
$m8 = Measure-Command {
    $resultAL = New-Object System.Collections.ArrayList
    1..$iterations | ForEach-Object {
        [void]$resultAL.Add(($_ + ($_ * $_)))
    }
    $resultAL | Out-File -FilePath $saveFile -Append
}
Remove-Item -Path $saveFile -Force

Write-Host 'Finished all measurements'
Write-Host ''

Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m1.TotalMilliseconds)
    Description = $m1Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m2.TotalMilliseconds)
    Description = $m2Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m3.TotalMilliseconds)
    Description = $m3Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m4.TotalMilliseconds)
    Description = $m4Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m5.TotalMilliseconds)
    Description = $m5Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m6.TotalMilliseconds)
    Description = $m6Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m7.TotalMilliseconds)
    Description = $m7Description
})
Write-Output ([PSCustomObject] [Ordered] @{
    Milliseconds = [math]::Round($m8.TotalMilliseconds)
    Description = $m8Description
})