Is Raspberry Pi fast enough to play a full HD stream from a network drive? And how Ralink chipset compares to Realtek RTL8188CUS chipset? Let’s find out.

After upgrading my home router to an 802.11n dual band (300Mbps + 300Mbps) with USB sharing support, I decided to test if it is possible to use it as a media server.

Comes out that the USB Wi-Fi adapter plays a crucial role in the ability to play an 1080p stream. But also the streaming method and the file encoding may affect the streaming performance.

Hopefully, I own two different Wi-Fi adapters so I managed to test them and find which one performs better. I’ve also tested different sharing protocols, finding out that on the slow powered RPi Samba does not perform very well.

The setup

Hardware
Raspberry Pi model B @ 900Mhz - Openelec 4.2.1
USB Wi-Fi Edimax 150N - Realtek RTL8188CUS
USB Wi-Fi Comfast CF-WU715N - Ralink RT5370
Router TP-Link TD-W8980 - N600 dual band

Both Wi-Fi adapters supports only the 2.4Ghz network and the nominal connection speed is 150Mbps, despite the router supports 300Mbps.

Streamed file specifications
H264 1080p video @ 11Mbps

I’ve tested several files with different qualities, however I’m reporting stats only for the highest quality one.

Testing streaming performance

Each test was run after a reboot, with no other action taken apart from the folder selection. The file was streamed for about 5 minutes but the average speed was collected every 30 seconds.

To get the data, I’ve used these tools while being connected through SSH to the Raspberry Pi:

  • Network link details: iwconfig
  • Network throughout: bwm-ng
  • CPU load: top
Realtek FTP Realtek SMB Ralink FTP Ralink SMB
Time to start 3s 5s 7s 10s
Top download speed 30 Mbps 15 Mbps 15 Mbps 15 Mbps
Avg dl speed (30s) 10-14 Mbps 5-9 Mbps 2-3 Mbps 1.5-2.5 Mbps
CPU load 40-50% 15-25% 45-55% 55-65%

Despite the Linux kernel supports the Ralink chipset family since 2011, the newer Realtek chipset performs way better on the low powered Raspberry Pi.
It’s also worth notice that with the Realtek Wi-Fi adapter the link quality was 5% higher despite the RPi being in the same place.

As you can read from the table, there is also a strong difference between protocols. FTP performs nearly 2x faster compared to SMB on the same hardware. I think that NFS should perform well too, but my router does not supports it.

To sum up, only the Realtek RTL8188CUS chipset on the FTP protocol is able to download fast enough to stream the video without interruptions.

Last tip: if you are unable to stream an MP4 file, double check my post on MP4 streaming issues.

TL;DR

Buy a Wi-Fi adapter with the Realtek RTL8188CUS chipset, use the latest RPi firmware and kernel drivers (update your distro) and prefer FTP or NFS protocols over Samba.