Very IMPORTANT and INTERESTING UPDATE: Due to some reason I just thought to do a complete new setup and this time I decided to again have openSUSE plus ubuntu. So I first reinstall lubuntu and then I installed OpenSUSE 12.2 (64 bit). Now, my DSL speed is working very normal and fine on opensuse. So this is very scary.

Is it possible for any operating system to manipulate my NIC so that it will work fine only on that operating system and not on another os?

Regarding positive thinking and not being paranoid, what is it that makes ONLY suse to get my NIC to work at normal speed but ubuntu can not do it? Not even fedora? Not even linux mint? What all these OS are lacking that enables suse to work great?

== ORIGINAL QUESTION ==

I 'was' on opensuse 12.2 when my dsl speed was normal. Yesterday I switched from opensuse to ubuntu 12.04 and speed decreased. It came to range of 7-10-13-20-25-kbps. Then I switch to linux mint, and then to fedora. Still slow speed. When I was in ubuntu I disabled ipv6 but still no luck. Now I am in fedora but this time with DIFFERENT ISP. And still I am getting very slow sped. So my guess is this is nothing to do with os. What can be wrong? Is this problem of NIC? Does NIC speed decreases over time? Does NIC life ends over time as with keyboard or mouse? Help please All the os I used are 64 bit and my laptop is Compaq Presario A965Tu Intel Centrino DUal Core. Interesting thing to notice is I get normal speed while downloading torrent inside torrent client softwares. This slow speed issue applied to download from any web browser or installing software using terminal.