The Test

I ran IxChariot throughput tests for powerline and wireless connections in all three test locations, so that we have actual throughput measurements to correlate with the observed streaming performance. Powerline throughput results are summarized in Figure 5.

Figure 5: IxChariot powerline throughput summary

Note that the living room test showed only 25 Mbps average powerline throughput, but no throughput dropouts. I have no explanation for the change from the HomePlug AV roundup results.

Figure 6 summarizes the wireless performance tests. This time, the living room location has the average highest throughput—60 Mbps. But higher throughput variation than powerline still puts 802.11n wireless at an HD streaming disadvantage.

Figure 6: IxChariot 802.11n throughput summary

After the throughput measurements, I played 720p and 1080p Megamind trailer clips and watched for playback errors. The results for the 720p clips are summarized in Table 1 and in Table 2 for 1080p. The corresponding IxChariot average throughput results are shown next to each of the results for easy reference.

Table 1: HD streaming behavior summary - 720p

While neither method produced trouble free playback 100% of the time during this short experiment, it's clear that there were fewer, more minor problems with 720p playback than with 1080p.

Table 2: HD streaming behavior summary - 1080p

Of particular note is I didn't get a crash or unrecoverable hang in any of the tests. The longest that the picture froze was for around 5 seconds with the lowest bandwidth 802.11n connection and 1080p.

Conclusion

There is both good and bad news in these results. The bad is that if you're looking for flawless 1080p HD playback from either 802.11n or powerline, you still won't get it. At the risk of repeating myself (again and again), if you want trouble free 1080p HD playback, use Ethernet, a local (to the player) file or a networked player with a big, intelligent buffer. 100 Mbps Ethernet will work just fine; you don't need Gigabit.

The good news is that if you can be satisfied with 720p or "1080p" files in formats encoded with lower bandwidth codecs, you have a good shot at getting a pretty enjoyable viewing experience with HomePlug AV. And if your distances are short, neighboring wireless traffic is low and you keep everyone else off your WLAN, you might even be able to watch 720p files in peace via 802.11n