The Thunderbolt card is a combo card with audio and lan. The card features a Killer nic E-2100 chip for advanced network settings that enhances your gaming experience. Lower ping reduced lag and settings for game packets priority. The audio is also an upgrade over the onboard audio.
Vision Tech makes the Killer nic in a stand alone nic card called the Vision Tech Killer Nic 2100 . When the Killer Nic is embebed on the motherboard or in this case a combo card they use just the chip and its called a E-2100 , there is no difference between the two and all the features and capabilities are the same. If you go to the Vision Tech site you can find out all the info you need.