original Killer NIC never really took off, as it was too expensive and it didn't really offer any huge benefit to most gamers. Bigfoot Networks are now back with a new, improved version called the Killer Xeno that is both cheaper and offer some new features.
The Killer NIC was meant to offload the CPU and it had 64MB of onboard memory. One of the other stand-out features was a built in USB port you could load custom applications onto the network card, although only a few applications were ever made.
The Killer Xeno NIC has evolved by using a PCI Express interface rather than PCI which should see actual Gigabit speeds this time, as the PCI bus isn't fast enough to be able to deliver the full Gigabit speed that was on offer from the older cards. Also new is the built in voice-chat accelerator, where the onboard NPU (Network Processor Unit) as Bigfoot likes to call it, offloads VoIP communications from the CPU. To take advantage of the voice-chat acceleration you have to connect your headset to the NIC, which is an interesting solution, although it seems like the NIC will interface with your sound card via an internal connector and as such there's no built in audio controller, but it's unclear at the time of writing how this feature works.
There will be two version of the Killer Xeon, with an Ultra and a Pro version. Unlike the PCI models, where there was a version with a faster and a slower NPU, the difference this time around is the amount of onboard memory, as both models has a 400MHz NPU. The Ultra version will feature 256MB of memory while the Pro version "only" gets 128MB. Additionally the Ultra version gets a swanky piece of metal and an onboard status display which seems to consists of an eight character LED display.
Price wise you're looking at $179.99 (€132/£122) for the Ultra model and $129.99 (€95/£88) for the Pro version. The Pro version should launch in April and will be available from Alienware and rather interestingly, EVGA. The Ultra version will be available in May.
You can find more details here