Hi All, I've solved this problem already, but was wondering if you guys knew what the cause was. Anyway, on to the story. We were just offered DSL in our area, and I am very pleased with the speeds. I am paying for the 5/768 service and I am surprised that I actually get those speeds...~5000 kbps download, and ~650 kbps upload while directly connected to the modem (Zyxel 660). (testing using »www.speakeasy.net/speedtest/ and »www.speedtest.net) I connected my wireless router (D-Link DI-624) and it connected fine...with the exception of my wireless. Download speeds while connected wirelessly max out at 1600 kbps. Upload is the same as direct connect to the modem. It's like I am limited to exactly 1600 kbps download while wireless...the needle shoots directly to 1600 and stops there. I have 4 wireless PCs, and 3 have this issue (all running XP). What throws me for a loop is that one PC (running Vista) has perfectly normal download speeds (~5000kbps) while connecting wirelessly. The speeds for all PCs return to normal if I am connected via ethernet cable to the router. I replaced the router with a Linksys, but the problem remained.The same 3 PCs stop at 1600kbps while wireless, and the same Vista machine downloads full speed while wirelessly. Turns out I had to download a small app called "Dr. TCP" and change the receiving window size on all of the XP machines (increasing the value to something above 100,000 fixed the problem). Supposedly the Vista machine has this functionality built in. Why the hell was this necessary?