Buffalo Nfiniti Dual-Band Wireless Router: Double your Draft-11n Wi-Fi fun

Wireless Performance - 2.4 vs. 5 GHz

The nFiniti is on the leading edge of what I think will be a trend back to dual-band WLAN gear. Once the 2.4 GHz legacy protection mechanisms are implemented, most users will find it difficult to achieve maximum throughput in the overcrowded 2.4 GHz band. So the move to 5 GHz will be necessary for many users.

However, 5 GHz wireless gear has been forever haunted by the ghost of first generation 11a gear, which had lower throughput vs. range performance than 11b/g products. 802.11a performance was long ago improved in Atheros' second generation chipset. But given the physics of RF propagation, everthing else being equal, the throughput vs. range curve for 5 GHz operation should still be under that for 2.4 GHz band operatoin.

Figures 20 and 21 show throughput vs. range for both bands on one plot for both 40 and 20 MHz modes. Please note the difference in Y axis scale between the two plots, as the Azimuth Studio application that I used to generate these plots doesn't currently have the ability to control the plot axes.

5 GHz vs. 2.4 GHz throughput vs. range - 40 MHz mode
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Figure 20: 5 GHz vs. 2.4 GHz throughput vs. range - 40 MHz mode

What is interesting is that the performance is so close between the two bands and in Figure 20, 5 GHz band uplink throughput actually exceeds that of 2.4 GHz in some portions of the curve. 20 MHz mode performance shown in Figure 21 shows a picture more like what I expected, with 5 GHz throughput rolling off before 2.4 GHz.

5 GHz vs. 2.4 GHz throughput vs. range - 20 MHz mode
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Figure 21: 5 GHz vs. 2.4 GHz throughput vs. range - 20 MHz mode

The conclusion you would reach from these plots is that you would expect similar performance from using either band—or at minimum, be able to remain connected in the same locations with either band. However, a quick walk around my home with the nFiniti card in my notebook linked to the nFiniti router showed that the Azimuth results don't accurately reflect the difference in real-world operation.

At one low-signal spot, the Windows Wireless Zero Configuration utility showed 4 bars of signal from the 2.4 GHz radio, but only one bar from the 5 GHz radio. But I've found signal level indications (and link rate especially) to not be accurate for other products, so I'm not basing my judgement solely on that.

The more telling test was done using IxChariot in my "black-hole-of-wireless" test Location 4. When connected to the 2.4 GHz radio, I was able to continue a test—although as much lower throughput—that I started at a location where both radios could connect. But when I connected to the 5 GHz radio and moved to the black hole spot, I promptly disassociated from the router.

I discussed these results with Azimuth before posting this review and they confirmed that the ACE's models do not incorporate signal attenuation differences between the 2.4 and 5 GHz bands. Azimuth and I will be discussing ways to have the ACE more accurately reflect "real world" 2.4 vs. 5 GHz operation in future reviews. But for now, these results can only be used for comparing performance of products within a given band.