Originally Posted by sammick
I am getting very fast internet speed with Comcast and my Ncard equipped laptop---like about
60Mbs---but when I plug the laptop into my N Airport Express, my speed is only 18-20Mbs--
Is speed limited on the Express---I have it set up to do iTunes and to join the network---
I think that there are a few things going on here:
1) You have to differentiate between Mb (megabits, or 1000 * 1000 bits) from MiB (megabytes, or 1024 * 1024 * 8 bits). Networking speed is always measured in Mb, but most Mac programs measure downloads in MiB. Make sure that your two measurements are using the same measuring system.
2) 802.11n's top theoretical speed is 300 Mb/sec, or about 35 MiB/sec ( that is 300*1000*1000/8*1024*1024). Then you need to take at least 10-15% off the top for protocol overhead (both WiFi and download protocol such as http and IP), and then some more for non-perfect radio environment.
Given all that you are not doing so badly. And if you are using an environment with both 802.11g and 802.11n deices, then you are also losing some speed to maintaining backwards compatibility.