Gamers are always hunting for a competitive edge, and the folks at Bigfoot Networks--now a part of Qualcomm Atheros--have long promised to deliver network interface cards that perform better with online games and other latency-sensitive applications. To demonstrate its prowess in this area, the company sent me two identical Alienware notebooks, one equipped with Qualcomm's Killer Wireless-N 1202 and the other with Intel's Centrino Advanced-N 6230.

Both NICs are dual-band adapters that can connect to an 802.11n router on either the 2.4GHz or 5GHz frequency band. Both also support two spatial streams for a maximum physical link rate of 300 megabits per second. Some gaming-laptop manufacturers, including Alienware, offer Killer NICs as standard equipment, while others offer the adapters as added-cost upgrades. You can also purchase one of these cards by itself and upgrade your existing notebook, provided that the system has an available Mini PCIe slot to host the card (a common feature on better notebooks). The Killer Wireless-N 1202 is certainly inexpensive enough: I've seen it selling online for as little as $35 (Intel's card is street-priced at about $30).

The key selling point of Killer NIC technology is its ability to identify the types of traffic traveling over your network and to assign higher priority to latency-sensitive traffic, such as online games, HD video, and audio.

Latency is a measure of time delay. When applications such as online games and streaming media encounter too much latency, you'll end up with visible and/or audible glitches and hiccups. If you're playing a first-person shooter with an online opponent, latency can render you a frustratingly easy target.

To evaluate each card's ability to combat network latency, Qualcomm provided me with its Gaming Network Efficiency (GaNE) benchmark to measure ping (the time required for a packet to make a round trip on the network) and jitter (undesirable deviations in signal timing). Qualcomm offered to allow us to examine the program's source code to ensure that there were no shenanigans.

Measuring ping and jitter using GaNE

GaNE measures real-time performance from two wireless clients at once, recording the results on a third computer that's hardwired to the network. This way, both client adapters are subject to the same environmental conditions--an important variable when you're benchmarking wireless performance. The tool measures latency between two networked PCs by sending a 100-byte packet on a round trip over the network every 50 milliseconds (100 bytes is the typical packet size on gaming networks, and 50ms is the typical interval between packets on the same). I used my longtime favorite 802.11n Wi-Fi router, a dual-band Asus RT-N66U, for these tests.

I set up the two wireless clients about 9 feet from the router in the same room, so no walls stood in between, and I connected them to the router's 2.4GHz network. I then performed six runs of the GaNE benchmark. GaNE reported an average ping time for the Killer Wireless-N 1202 of about 1.5 milliseconds, and an average ping of nearly 4 milliseconds for the Intel card. What's more, GaNE measured one-and-a-half times more jitter with Intel's card than it did with Qualcomm's. The Killer NIC delivered similar performance when I switched the clients over to the router's 5GHz network--slightly less than 2 milliseconds--but Intel's card registered a much higher average ping of nearly 8 milliseconds.

TCP throughput

I also used the Asus RT-N66U to compare the adapters' TCP-throughput performance, using JPERF (the Java front end to the TCP-throughput benchmark iPERF). The two adapters traded places on the 2.4GHz frequency band, but when the Killer Wireless-N 1202 won, it won by a significant margin. When the client was in the same room as the router, 9 feet away with no walls in between, it was 10.7 mbps faster than Intel's component. And when the client was in my home office, 65 feet away and separated by three insulated interior walls, the Killer NIC was more than 25 mbps faster. At the two locations at which Intel's adapter prevailed--in the kitchen (20 feet from the router) and in the home theater (35 feet from the router)--the margins were just 0.5 mbps and 4.0 mbps respectively.

When I tested each adapter on the 5GHz network, Intel's NIC performed much better--at close range, at least. In the bedroom test, the Centrino Advanced-N 6230 delivered TCP throughput of 196.0 mbps to the Killer's 121.0 mbps. And when I moved the clients to the kitchen, Intel's component was more than twice as fast as Qualcomm's. But when I tested each client at longer distances, the tables turned, and the Killer NIC delivered dramatically higher TCP throughput than Intel's card. In the home theater, the Killer delivered 81.1 mbps to the Centrino's 30.1 mbps; and in the home office, Qualcomm's card produced a rate of 63.8 mbps to Intel's 34.9 mbps.

Upgrade to 802.11ac if you can

So Qualcomm's Killer Wireless-N 1202 is a great Wi-Fi adapter. What happens if you've upgraded--or are planning to upgrade--to a router based on the new 802.11ac standard? Well, such routers are backward-compatible with 802.11n, so a Killer NIC will still work with one. But if that's where you're at, I think the better bet is to switch to an 802.11ac adapter. In fact, some notebook manufacturers--including Alienware--are already offering 802.11ac Wi-Fi adapters as standard equipment on higher-end laptop models (and tellingly, Alienware does not offer the Killer NIC--which is currently available only in 802.11n configurations--as an option on those models).

You should also remember your other option: a hardwired ethernet connection. If you don't mind stringing cable, a hardwired connection will be faster than any wireless setup, and you won't have to worry much about latency or jitter at all. But most people don't want to hassle with cables these days, because wireless connections are so much more convenient.

If you're buying a new gaming notebook and the seller offers the Killer NIC as a modestly priced upgrade (say, no more than $30), it's definitely worth the money. The same goes if you're upgrading a laptop with a Mini PCIe expansion slot and two internal antennas (Qualcomm's Killer Wireless-N1103 supports three antennas). But if you can get an 802.11ac adapter, that would be an even better investment. In fact, I'm surprised Qualcomm isn't already offering a Killer NIC based on that spec.