I'm having a problem with one computer. Uverse delivers 14 Mbps and all devices in the house except for one computer get that. This one computer (I'm on it now) gets about 3 Mbps. A UVerse technician came over today and installed a new gateway and narrowed the problem down to this computer. I've replaced the cable and just installed a new NIC card, with no change. What's left? Could it be the motherboard needs to be replaced to solve this problem? (ATT mailed a new gateway earlier in the week and immediately after setting it up this computer also got about 14 Mbps for a few hours. When I retested 12 hrs. later the speed had dropped to where it is now, which is where it was when I first requested the service call.) Thanks.