Bigfoot has just released its Killer Xeno PCIe gaming network that aims to improve your frames per second and pings.
It is basically a mini computer by itself that does all the work required by being powered by a Linux-derived distro.
It is compatible with virtually any PCIe slot, boasting a native PCI-E chip with support for voice-chat acceleration.
The odler Bigfoot Killer NIC was reviewed by IGN and they did find the card bumped the framerate on the bundled F.E.A.R. from 74 to 86 fps, and the ping went from an average of 67ms to 45ms.
It is arguable just how much use this card would be as your pings will likely be more effected by your ADSL and the quality of your wiring.
Considering the Xeno costs $130 and $180 for the 128MB RAM and 256MB RAM, respectively you may find if you are building a new PC that it is better spent putting the money towards a better graphics card.
However if you have money to burn and already have the best graphics card then I am sure this card will providing that extra boost you are looking for.