Bigfoot Networks' Killer NIC "gaming network accelerator" has yet to hit stores, but the card has landed in IGN's labs and been the subject of an early review:

The install went down without a hitch, though it's worth noting that PCI slots are becoming a scarce commodity in gaming rigs. Our single ATI X1900 XTX system only has room for two extra PCI cards, which we've now filled with an Ageia PhysX card and the Killer NIC. If we were running a CrossFire setup we'd be down to one, if any, free PCI slots and would have to choose between the PhysX and the Killer NIC. Considering that the Killer NIC is a product specifically designed for the hardest-core gamers Bigfoot is going to have to hope most people haven't already jumped about the Ageia train.

Once the drivers were installed we disabled the motherboard's Ethernet controllers and turned on the Killer NIC's LLR functionality. Based upon some rough benchmarking, without the Killer NIC our test PC (AMD FX 62 2600, ATI Radeon X1900 XTX, 2 GB RAM) runs F.E.A.R. at 1024x768x32 with details maxed and 2xAA-2xAF at an average of 74 fps though two 15 minute sessions. Our ping to server ranged from 40-80ms, and our average worked out to 67ms over the two sessions.

After installing the Killer NIC we got back on the same F.E.A.R. server and played on the same map. The improvement with the Killer NIC was noticeable and impressive. Pings to server dramatically improved, generally ranging from 17-50ms, averaging 45ms over another two 15 minute sessions. FPS also got a nice bump, jumping our average from 74 to 86 fps.