Odd WiFi speed issue with W520 and Intel 6205

[cheetahdriver]

Did some rework on my incoming bandwidth last week, and after taking Verizon to task for several days, it would appear the problem is with my W520. Using Wifi, I am getting speeds of about 5-900Kb/s off of the new network, but using my desktop, I am getting 4800-6800Kb/s. If I hard connect (cable), I get the same speeds off of the W520. I have so far

1) Gone to the Intel Centrino site and updated the driver using their driver update tool. This appeared to be a full major rev (version 14 from lenovo vs ver 15 from Intel) upgrade.

2) Went through all of the suggested settings that were on the Intel site.

3) Tried a second (backup unit, identical configuration) W520.

Nothing so far has made any difference. The odd thing is that I can get into my second network and get 1400Kb/s just fine. I would happily entertain suggestions....