Raspberry Pi network speed comparison: model B+ with in-built ethernet vs model A+ with USB wired or WiFi dongle

Background

The Raspberry Pi Model A+ is cheaper than the Model B+, but it lacks a network connection.  Is it cost effective to buy this cheaper model and plug in a USB network dongle?

Method

Passwordless SSH copy a 167 Mb file to the Raspberry Pis and measure the time with the 'time' command.

Results

	Cost of RPi, power supply and postage £	Type and cost of network adapter £	Time to write 167 Mb
Model B+ wired	28+5+2	0	1m36.787s
Model A+ WiFi	18+5+2	148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter 6	1m49.823s
Model A+ Wired	18+5+2	0fe6:9700 Kontron (Industrial Computer Source / ICS Advent) DM9601 Fast Ethernet Adapter 1.62	∞ (stalls at 2% and Broken pipe = useless)

Discussion

Whilst the Kontron DM9601 has been useful for SSH terminal connections, it failed on receiving a 167 Mb file.  This is clearly the most useless option.

The fastest option is to transfer into the built-in ethernet port on the Model B+.   The hardware for this costs £35.

The cheapest option is to transfer into a WiFi adapter in the Model A+.  The hardware for this costs £31.  The transfer rate is only 12% less.

Limitations of this study include

• A single file was transferred.  The result may vary for many small files.
• The A+ with WiFi was very close to the wireless hub and therefore the speed may be better than over longer distances.
• SSH does not just test the connection, it also tests the processor.  Double the amount of RAM in the Model B+ may also have been a contributing factor.
• Different memory cards were used in each Raspberry Pi.
• No investigation as to why the Kontron DM9601 failed.

Conclusion

For speed buy a Model B+.  If a WiFi connection and no other USB ports are needed is needed then the A+ is marginally cheaper.  Looking for a cheap wired dongle is a false economy.