comaprefilebytes.ps1

0..10 | ForEach-Object {

    Measure-Command {&{
        $fileA = (Get-Item .\lorem1.txt).OpenRead()
        $fileB = (Get-Item .\lorem2.txt).OpenRead()
        for(($i = 0), ($z = 0); $i -lt $fileA.Length -or $z -lt $fileB.Length; $i++, $z++) {
            if(-not $fileA.ReadByte().Equals($fileB.ReadByte())) {
                break
            }
        }
        ($fileA, $fileB).ForEach('Dispose')
    }} | Select-Object @{ N = 'Test'; E = { 'Byte-by-Byte Comparison' }}, TotalMilliseconds

    Measure-Command {&{
        $fileA = (Get-Item .\lorem1.txt).OpenRead()
        $fileB = (Get-Item .\lorem2.txt).OpenRead()
        $bufferA = [byte[]]::new(1kb)
        $bufferB = [byte[]]::new(1kb)
        while(0 -notin $fileA.Read($bufferA, 0, $bufferA.Length), $fileB.Read($bufferB, 0, $bufferB.Length)) {
            if(-not [System.Linq.Enumerable]::SequenceEqual($bufferA, $bufferB)) {
                break
            }
        }
        ($fileA, $fileB).ForEach('Dispose')
    }} | Select-Object @{ N = 'Test'; E = { 'Chunk Comparison' }}, TotalMilliseconds

} | Group-Object Test | Select-Object @(
    @{ N = 'Test'; E = { $_.Name }}
    @{ N = 'Average'; E = {
        [math]::Round([System.Linq.Enumerable]::Average([double[]] $_.Group.TotalMilliseconds), 3)
    }}
)

comparechunks.ps1

& { param($FirstFile, $SecondFile)

    try {
        $fileA = (Get-Item $FirstFile).OpenRead()
        $fileB = (Get-Item $SecondFile).OpenRead()
        $bufferA = [byte[]]::new(1kb)
        $bufferB = [byte[]]::new(1kb)
        while(0 -notin $fileA.Read($bufferA, 0, $bufferA.Length), $fileB.Read($bufferB, 0, $bufferB.Length)) {
            if(-not [System.Linq.Enumerable]::SequenceEqual($bufferA, $bufferB)) {
                return $false
            }
            $true
        }
    }
    finally {
        ${fileA}?.Dispose()
        ${fileB}?.Dispose()
    }
}

results.md

Test                    Average   
----                    -------   
Byte-by-Byte Comparison  57.832   
Chunk Comparison          1.223