Ok , I have recently been having this problem and I have not got the slightest clue what's going on , so thought I would bring it up here see if anyone else has dealt with the problem .
I load the game up fine then I click on multilayer lobby, this is when the trouble starts , my fps shoots way down to 0.4 fps etc, it takes forever to scan usually brining up nothing/crashing as its lagging out.
On the odd occasion I wait long enough and it might eventually finds a server the ping is usually 900+(even tho my inet connection is fine) , if im lucky enough it will let me in and the game is fine to play. So the only issue I have is the lobby issue.
Any help would be much appreciated , as missing not beeing able to play such a good game
EDIT!!!!!!!!!!!!!
I recently opened up "rgl_config.txt" and changed max_number_of_connections = 10 to max_number_of_connections = 6, and it seamed to help a little .