I upgraded to the 825 from an old Linksys G router, and I'm now experiencing significantly slower speeds. It's particularly noticeable on torrents; on the G router I was routinely getting 200k/s downloads, and on the 825 I don't think I've broken 70. I disabled QoS in case that was the problem. The router is reporting that I'm connected at the full 300 mbps, and I'm literally sitting next to the router (and only getting 80% signal strength?).
I should also mention that my upload speeds seem just fine...I'm uploading at about 150-200k/s. For some reason my download speed will barely break 75k/s
My wireless adapter is an Intel 5100 in my Vaio SR 190 laptop. I'm having issues with the 5ghz band as well, but I'd like to get the 2.4ghz network set up before I start worrying about that.
If there's any other info I can give which would help, please let me know.