The script is a little old but still works. However, on boxes with very large amounts of RAM (100G+), top doesn't give an answer in K anymore and the script breaks. I took out the if statement in the main loop that grabs the memory and replaced it with:

my $free= `free|fgrep Mem`;

if($free=~/Mem\s*:\s+(\S+)\s+/i)
{
        $totalmem = convtok($1);
}
else
{
        die("Can't find memory info\n");
}
[download]

just above the foreach and that worked for our 680GB ram monster.