Wireless Performance - 5 GHz

Figure 10 shows test results for the 5 GHz, 20 MHz mode. Average 1 minute throughput is 55 / 56 Mbps, about the same as with 2.4 GHz.

Figure 10: Up and downlink throughput - 5 GHz band, 20 MHz bandwidth

The 5 GHz, Auto 20/40 MHz mode plot is here, where you can see the highest throughputs obtained for the 855: 91 Mbps up/down; 79 Mbps down; and 77 Mbps up. Note the severe mismatch between up and downlink when running simultaneously in both directions.

The walk-around test using the 5 GHz radio didn't set any records. While throughput came in around 35 Mbps down and 25 Mbps up in Location 3, I wasn't able to even connect in Locations 4 and 5.

Security mode throughput

Since the 855 is Atheros-based, I expected at least a 50% throughput reduction when using either WEP or WPA/TKIP wireless security. And that is what I found (Figure 11).

Figure 11: Security mode throughput comparison - 2.4 GHz downlink

Mixed STAs, Neighboring Legacy WLANs

I checked performance with a mix of draft 11n and 11g clients (STAs) in the DGL-4500 review, so didn't repeat those tests here. As a reminder, the tests showed the behavior that I've come to expect: the 11g STA gets knocked down to around 6 Mbps and the 11n STA gets its throughput cut by around half.

Since I've already looked at how the Atheros XSPAN chipset behaves when encountering a "legacy" (802.11b or g) WLAN operating in its 40 MHz mode extension channel, I didn't check it this time. As a reminder, the Atheros seems to be a bit more "legacy" friendly than other chipsets since it doesn't completely knock the 11g WLAN off the air, like products based on other chipsets do.