The ISP tech guy came with his laptop and found that speed is 1Mbps in his laptop but upload was 0. Also I showed him the AI NET 2 LAN diagnostic tool in my BIOS which showed pair 1-2, 3-6 as SHORT with 4 meter distance. So he changed the router, cable and power adapter. He tested again in his laptop and now it was 2.5Mbps. He unplugged it and plugged it in my desktop. In the AI NET 2 LAN diagnostic tool in my BIOS the pair 1-2, 3-6 are NORMAL now. So I thought it will resolve the problem. But to my surprise the speed still showed 500kbps.
I had one NIC so added it in PCI and checked, still 500kbps. My motherboard have ASUS EXPRESS GATE so used it to test the speed. It showed 700kbps.
The tech guy again checked in his laptop with speedtest.net and speed was > 2Mbps.
I am really frustrated as not able to pin point the issue.
Please help, let me know what other details are needed.