According to PC World:
...at the 2009 Game Developer's Conference, Bigfoot Networks has two announcements. The first: they are releasing the $130 Killer Xeno Pro card. The big deal this time around is that they've been able to get prices down, beef up the memory and pack on an additional chip that can offload the voice chat. A 400GHz NPU (as in Network Processing Unit -- oh, joy, another acronym!) bypasses the Windows network stack while an integrated audio chip offloads VoIP.
I know gamers are all about low latency while trash-talking their opponents using VoIP, but $130? Aren't PCs and NICs fast enough these days? Well, if you you have to have the every pico-second of latency minimized and want to shell out $130, then by all means have at it.