On my daughter's VAO laptop, there is the usual very low end wifi card, so slow that I usually have it plugged into my home network. It is a gig port, hooked up via a gig switch through about 70 feet of cat 5 and then to my WNDR4000 router. About a year ago, I noticed that it only got a 100mbps connection. Reconnected right to the router, still 100mbps. And yes, I checked the device manager and other settings. Eventually had Sony come and check it (really long and painful story here) and the tech confirmed the problem and replaced the mobo on the spot. It worked at 1gbps just fine at that point.

Back from college many months later, it was back to 100mbps. Again, checked settings, etc. No hint of any other problem.

So I'm curious; has anyone out there also seen this problem, know its cause, any solution?

Yes, laptop fully patched and up to date. Otherwise working normally. No, I'll never buy another Vaio (for many reasons).