Questions about my router set up and performance

[supersrsman]

Before I begin, I'd like to say that I'm pretty much a complete noob when coming to the concepts behind networking.

I recently purchased a netgear n900 with a western digital mybook essential 1.5tb. The external hard drive is attached to the netgear n900 by way of usb.

I'm having some problems with some of the wireless users in the household.

I understand the netgear n900 is capable of outputting 450mbps speeds. Both laptops were only receiving 72mbps.

I thought it had something to do with the wireless network cards installed on the laptops.

Under the devices list, I saw:

- 11b/g/n Wireless Lan Mini for the first
- something like 1x1 b/g/n Wireless network card

I sort of understand that the 1x1 describes the send and receive antenna configurations. And 1x1 has a theoretical limit of 72mbps?

Also, with the external hard drive connected, I'm getting spotty transfer speeds.

Wired to the router, I can get around 6-8MBps read/write speeds.

On my laptops, I can get 5-7MBps read, but a only around 300KBps write.

Is the slow write speed a limitation due to the laptops? Why am I not getting 72mbps (9MBps)?

Also, shouldn't my desktop directly connected to the router have significantly higher read/write speeds? Does this have to do with a limitation of the format of the external hard drive?

Any help would be appreciated. I'm sorry if I missed something crucial.

Thanks!

 

[stevech]

First, the indicated WiFi "link data speed", say, 36Mbps or so, is the raw rate over the air. This is reduced due to overhead of the WiFi protocol so that the net yield is ideally about 60% of the link data speed. The net can be lower yet if your WiFi is on channels that have heavy traffic from other WiFi users nearby. (You can change channels if this is the case, to channel 1, 6 or 11).

Secondly, 802.11n has many variants and options. If you're getting net yield speeds about 50Mbps or so, that's good, for basic 11n. The speeds decline quickly with reduced signal strength. And the limiting factor is usually the laptop to WiFi router link, as the laptop often has a weaker transmitter and inferior antenna. Most consumer WiFi routers (and access points) do not display the received signal strength. It's a mistake to assume that the laptop's received signal strength display (to-laptop) will be the same for the from-laptop direction to the router.

With an ideal signal strength (close range, near line-of-sight), a laptop in the 20MHz bandwidth mode can achieve perhaps 50-75Mbps or so. To get to 300Mbps, you need that option in both the laptop and the WiFi router/AP. In practical terms, due to distance/walls/floors, those 100+ Mbps speeds are rare.