so i have installed ubuntu four days ago on my toshiba SATELLITE-C855-2CF and everything is going well, but i noticed that my wifi connection is slow and when i did a speed test online i found that i have only 0.9 Mbps and when i did the speed test on windows i have 4Mbps so can someone tell me how can i fix this problem ? if don't find any solution for this problem i'll have to go back to windows and leave ubuntu.
You have a pretty marginal connection (quality 34/70), 6967 invalid misc packets, and your connection speed has dropped back to 18Mb/sec from the max of 54 for g networking. Try improving your signal by moving your machine relative to the access point. Another thing to check is the outside interference on your channel. Use
sudo iwlist scan
To see all the nearby access points and their channels/ strengths. If you see many others on your channel (and really only 1 6 and 11 do not overlap, so nearby ones interfere too), try changing your channel.
I believe that there are conflicts with the driver, so you can try installing the Official drivers for the WLAN NIC.
This answer should help you [but, a newer version of the driver can be downladed from here Other steps remain the same.]. I'm pasting the answer below:
Realtek is making the official Linux driver available unofficially (via Dropbox)
Support for the RTL8273AE-BT has been added by Realtek in the 92-series driver, version 0006.0514.2012. For unknown reasons, neither the Windows nor Linux drivers are available on their website (yet). But Realtek tech support has been providing a Dropbox link with the source code/firmware tarball which numerous users have reported as working.
uname -ato know it. This version broke my wifi connection (95% of packets dropped) but not on all wifi routers.