Okay I decided my old wireless router was broken and caved in and bought a new router, a Linksys WRT610N (unfortunately v1, I'm not sure if v2 is even available in the UK). I paired it up with two Linksys WMP600N.
Problem is performance is fairly bad at 2.4Ghz (it's appalling at 5Ghz, barely working at 6 metres), one PC is pretty bad at it's weakest the connection is still fairly stable at 3.5Mbps, but normally it's between 81-270Mbps. That PC is 6 metres from the router and it almost has LoS (just clips a doorway). The second PC is having serious problems, sometimes it is okay others it just times out when you try to ping the router. Now the PC has a wall between it and the router, but the distance is about the same as the first PC. The thing is the old router and wireless cards worked perfectly, using G and Pre-N they get much better signal strengths in the same locations. I'd still be using them except for the fact the cards don't work under Vista or Windows 7, and the router refuses to assign a correct IP address to Vista or Windows 7 clients.
I've tried all sorts of settings for the router, pretty much everything you can imagine and different drivers for the PCI adapters. Nothing sensible seems to improve the situation, moving the router into the same room as the computer obviously fixes the problem, but that requires a long cable to the modem which is not feasible. Now I could find datasheets with the RF power of the Linksys stuff, 13dBm for the router (11dBm at 5Ghz), and 13.5dBm for the cards, now I'm not an expert but that seems a bit low when the datasheet for v2 of the router is listing 17dBm which is almost twice the power, I think . The old stuff was Belkin and they, typical of Belkin , don't provide that info.
Now here is the question. Should I buy another router or adaptor that is more powerful? Or is there some better/cheaper solution?
I'm currently trying to get the e-retailer to take back the WRT610N and/or the WMP600Ns as I think that 6m isn't that far to expect a wireless connection to cover, is that unreasonable? I am not hopeful after my first contact though.