Hello,

Been trying to solve this for a while. I have the w520 with Intel Ultimate 6300.  I did a clean install and everything, all latest drivers, but my wifi only connects to my router at 54 mbps at 5 GHz. It's not my router as my HTPC can connect fine at ~300 mbps at 5 GHz.  Any idea? 

Thanks.

found the problem..  wow cant believe this, you need to enable your bluetooth radio in order to go beyond 54 mbps..

just turned on my bluetooth radio and signal jumped to 240 mbps, good enough

That makes no sense, my T510 will connect at 300Mbps with all the radios except the wifi (Intel 6250) disabled.

like you said, your T510, mine's a W520, and with Intel Centrino Ultimate 6300.

Whatever the case, for those with the same problem; enabling bluetooth will solve your cap at 54 mbps with the intel wifi. I don't know why Lenovo designed it to be like this, maybe something to do with the antenna. Anyway, hope it helps

The only difference between those two cards is mine supports WiMAX and yours has 3x3 antenna. The wifi driver is even the same.