Here is my config and test results:
All of the recommendations so far are incorrect and/or baseless. This is an Intel bug/defect and they need to fix it in all of their WiFi.
1 - Cisco/Linksys E3000 (latest FW (Ver.1.0.02 (build 4)tech support made me)
2 - T410s Intel 6200 Advanced-n AGN (latest driver 184.108.40.206 tech support made me)
wireless max download 14Mbps/upload 20Mbpswired max download 50Mbps/22 Mbps
1 - T510 Intel 6250 WiMax - Not the latest (ha ha ha)
wireless max download 15Mbps/upload 20Mbpswired max download 50Mbps/22 Mbps
1 - T61 Intel 4965AGN - Latest driver on my own 220.127.116.11
2 - iMac 20 (2009 model) Built-in AirPort Extreme (802.11n - whateverthe all powerfull Apple System Updates makes me do - recent)
wireless max download 40Mbps/upload 18Mbpswired max download 60Mbps/20 Mbps
ISP - 50Mbps download/10Mbps package just upgraded from 16/3
I called Linksys/Cisco, waste of time. They told me to return the router.
I called Lenovo, actually they tried but still they referred me to Intel.
I called Intel let's just say...they aren't happy.
Oh yeah...this IS an Intel issue.
Complete agree this is an INTEL issue have tested other manufactures and without messing with my router spec's get at least 150 mbs of speed, the problem here is what you spend (waste) on INTEL products and you know what a waste.