"After spending an evening of gaming with and without the Killer NIC and Killer K1 on both our Windows XP Pro and Windows Vista Ultimate test systems it was the unanimously agreed by all that the Killer NIC and Killer K1 is not worth the added $180-$250 cost. The Killer NIC and Killer K1 did reduce our pings and improved frame rates, but by less than 5%. The difference was so small that no one could correctly tell when the Killer NIC was or wasn't installed in our 'blind' taste test, which was rather alarming... "