I started by removing all PCI adapters from the system (Sound adapter, modem board, Ethernet adapter), leaving the system with only a graphics adapter and the DWL-520 installed.

I repeated the tests and found that the problem was still present.

The next step was to disable as many of the on-board devices as possible, so I started by disabling the USB support.

That fixed it! The DWL-520 worked perfectly!

I'll try and find a driver update for the USB hardware on that mboard and post here again if this solves the problem.

1. The DWL-520 worked fine on two of my older machines, an A-Bit BP6 (1999) and a 1998-vintage 300MHz Celeron machine.

2. The DWL-520 did not work reliably on an ASUS A7V machine (2001), although it installed correctly, could ping (but only with considerable packet loss), and it could transfer small files.
It seemed to "hang" during the transfer of large files.

3. I therefore don't think the PCI 2.2 issue is the problem, as none of my machines have PCI 2.2, and the DWL-520 worked fine on the older boards.

By "worked fine", I mean:

1. Continuous pings worked. Not one packet was lost over several hours of testing.

2. Large file transfers (100 MB) worked repeatedly. Speed was good.

3. Range was good, although I only tested up to about 30m or so.

So it would seem that the ASUS mboard and the DWL-520 just don't get on with each other.

Chris.

That's right.
I am lucky than Joe. I spent a whole Saturday afternoon figuring it out. I have tried the DWL-520 card on three of my PCs.