Several months ago I bought a Linksys WNR834b v2 Wireless-N router. Flashed DD-WRT (build 12548M) to it shortly after it arrived, tinkered with it a bit, and got reasonably good wireless speeds in short order - 2.5 megabytes per second across the local network from my (wireless) laptop to my (wired) media PC using the laptop's internal wifi adapter, 3.5 using a USB plug-in N adapter in the laptop. Windows 7 Pro reported that the internal was clocking at 65Mbps, and that the USB was clocking at 135, if I'm remembering correctly...
Well, at some point in the last month or two, my speeds have dropped off. I'm now lucky to get 700K/sec transfer from one to the other, and I haven't the slightest idea why. Windows is still reporting 65Mbps and 135Mbps for the two adapters, and I'm not seeing any unusual traffic to or from the laptop in either Windows's built-in traffic monitoring or in DD-WRT's. I've tried rebooting both my computer and my router ("Did you try turning it off and back on again?") but that hasn't helped. I've tried futzing with my router's broadcast channel, and that hasn't helped either. My SNR is consistently around 30, give or take six-ish, so it doesn't appear that interference is the issue. My outgoing speeds on the wired computer are fine; speedtest.net reports a download speed of 34.15Mbps, so whatever's going wrong is either on the router's end or is something to do with my laptop. Or possibly my apartment, but nothing's changed substantially in here in nearly a year.
I'm frankly at a loss. I haven't the slightest idea where to go with this. If it helps at all, the internal wifi adapter is a Broadcom 4313GN; the plug-in runs a RealTek RTL8188CUS chipset. Can anyone give me any tips to get my speed back up to what it was?
Edit: Aw crap, this should probably be in the Wifi subforum, shouldn't it? I'd appreciate it if someone with the power to do so would move it. Thanks!