My home network is running on an ASUS RT-N66U with Tomato Firmware (1.28.0000 MIPSR2-112 K26 USB AIO-64K). I have a single wireless SSID defined with WPA2 Personal + AES. I've had an ongoing problem where my wireless card will periodically become unusable, that has expressed itself in a couple of different ways (the machine typically runs Windows 7 64-bit).
When I first started using this network, I was running on an Atheros AR9485WB adapter. When I was running this adapter, the network would disconnect entirely. After reading around online, there seemed to be a consensus that this card had troubles connecting to WPA2 networks. I tried several versions of drivers, and didn't get any noticeable improvement. I did not try switching to a WPA- or WEP-secured network, because it wasn't going to be a permanent solution and there's a limit to the actions I can take that would dump roommates off the network and annoy them.
I eventually switched to an Intel Centrino Advanced-N 6235 on recommendation from the same sites, and am using the latest drivers-only 64-bit install from this link: Intel Download Center Drivers. The version reported there (I assume the Intel ProSet driver package version) is 16.1.5, and the version reported in my device manager (I assume the actual driver version) is 188.8.131.52.
This has improved the situation somewhat in that the network does not completely disconnect. However, it will still achieve unusable latency (pings of 1000-3000 ms to the router, if it resolves at all, which is not guaranteed with this state), but is completely fixed by turning the wireless adapter in my machine off and then on again. I'm running a couple of pings in the background to the router itself, and to another machine on the network,
I'd be happy to dive deeply into this, inspecting packets with Wireshark or any similar tool, but I'm not even exactly sure where to begin, and the nature of these problems tends to be so vague that searching online for tutorial material for diagnosing this specific problem has been an exercise in frustration.