Reducing Computation Time with Multiple Parameters

My script is running in O(n) time while checking multiple parameters; I'm seeking a way to get closer to O(1) time if possible. Please ignore the fact that I am utilizing excel; there are other portions of the script that are utilizing the methods. All suggestions are appreciated.

$rowMax = ($sheet.UsedRange.Rows).count  
$count = 0
$countDelete = 0

#Declare the starting positions
$rowCompName,$colCompName = 1,3

#Checking Loop
for ($i=1; $i -le $rowMax-1; $i++){                   
    $CompName = $sheet.Cells.Item($rowCompName+$i,$colCompName).text.ToUpper()

    #Items Processed
    $count++

    #Removal of non-ND machines
    if($CompName -eq ''){
        continue
    }

    $CompName = $CompName.Substring(0,5)    

    if($CompName -ne "Name1" -and $CompName -ne "Name2" -and $CompName -ne "Name3" -and $CompName -ne "Name4") {
        $returnsTrue = $sheet.Cells.Item($rowCompName+$i,$colCompName).EntireRow.Delete()
        $rowsDeleted++ 
        $i--   
        $rowMax--
        $countDelete++
    }

}