Upgrading Router, Should I Upgrade My Modem Too?

IMO buying an 802.11ac router is premature -- the standard is not yet mature and will change so future devices likely will not work with what you buy now. Also, to make a difference all of your devices will need to have 802.11ac wireless adapters.

A properly configured N router makes a lot more sense at this time. But to get over 54Mbps you must use the N router as N only, use WPA2 security, and personal AES encryption, otherwise N defaults down to the G speed cap of 54Mbps. All of your devices must have N adapters and must also use WPA2 with personal AES encryption. Any device that doesn't have an adapter that supports those will not work on the network once it is N only WPA2/AES wireless network.

I have a wireless N router running in b/g/n mode with 2 PC's with N adapters and 1 PC with G adapter. I tested internet with speedtest .net and got +-20Mbps on my N PC's and +- 10 Mbps on my G PC. My advertised internet speed is 20Mbps so I am fully utilizing that with my N PC's. So it does not appear as my router is defaulting to G speeds even though I have it in b/g/n mode.

Original Poster - I wouldn't upgrade the modem unless you are having issues with connections or you aren't getting your advertised speeds and it is the modem causing it. I have an older modem, a Motorola SB5101 (DOCSIS 2.0 compatible) and get over 20Mbps through Comcast. I have heard that modem can do 35 Mbps or more... so there is no reason for me to get a new one.

Anyway, put the new router in, check to see what speeds you get and go from there.

I don't care what it seems like (all you are testing is your relatively low ISP speed and not your LAN) -- look at some actual information on the N standard -- if you use an N router in G/N mode and either a G device attaches, or you are not using WPA2 with AES encryption for all devices, the maximum speed that wireless can support is 54Mbps (G), rather than the 150Mbps or higher N maximum limit. Speedtest.net is simply testing your ISP speed and tells you little about your internal network speeds -- for that LAN Speed Test is the proper tool: http://download.cnet.com/LAN-Speed-Test/3000-2085_4-109... Perhaps you don't actually transfer files over your network so the point is moot for you.

And for the best LAN transfer rates gigabit Ethernet is superior, delivering over 800Mbps transfers if all components support gigabit -- adapters, cables, switches and routers.

True, I wasn't thinking about LAN speed, only online connection speed. Just for fun I used that tool and was able to see a jump from 38Mbps to 56Mbps when using N only and WPA2 and AES versus mixed mode. Interesting.

Good information, I appreciate you sharing.

Sure, just like powerline numbers though I rarely see N running over 100Mbps. There is a lot of marketing talk in those maximums. The only truly reliable speeds that I find consistently are gigabit wired, which on tests from SSD to SSD over the network consistently achieve about 830Mbps -- the difference is due to network overhead.

But wired transfers are great for large files, like the Bluray images that I stream in full definition. Wireless just doesn't cut it, although I have higher hopes for 802.11ac in a year or so when it becomes standardized.