Hello michael-y1, sorry to hear that you are experiencing trouble with your wireless adapter. The connection speed/range and throughput depends on a lot of variables, mostly how it was integrated, since a specific amount of resources are made available for the port, antennas are installed and a customized hardware. The Intel® Centrino® Advanced-N 6200 maximum theoretical speed is 300Mbps while the Intel® Centrino® Ultimate 6300 is capable of 450mbps.
You may check the link below for additional information and Troubleshooting, (if you haven’t already)
http://www.intel.com/support/wireless/wlan/4965agn/sb/CS-028449.htm
