Sony VAIO computer - Manual (Page 145)

Why is the data transfer speed slow?
 The wireless LAN data transfer speed is affected by distance and obstructions between devices and access points.
Other factors include device configurations, radio conditions, and software compatibility. To maximize the data
transfer speed, move your computer away from obstructions or closer to any access point you may be using.
 If you are using a wireless LAN access point, the device may be temporarily overloaded depending on how many
other devices are communicating via the access point.
 If your access point interferes with other access points, change the access point channel. See your access point
instructions for more information.
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