it could be a few things:
1) probably the server has a bad connection
2) you have a bad connection to that particular server or a specific country (outages in the country local to the server could cause you problems but another person may experience nothing)
3) your current setup cant handle numerous players firing guns and throwing nades etc (great networking usage and more cpu performance required).
possible things to check:
first off DELETE ALL - DEMOS, SCREENSHOTS, and CUSTOM MAPS from the game directory (back them up to a different folder if need be for now)
it may sound weird but this is actually what causes me issues with my game and FPS once I start to have more than a few maps i get crazy FPS and its repeatable too so I know their seems to be a link to number of maps/files and performance.
Windows 7 networking differs from XP: make sure your using a network cable not wireless for tests.
try a different DNS provider from your ISP: OpenDNS is a good one : 208.67.220.220 and 208.67.222.222
trying backing up your config and removing it to start with a fresh one on windows 7
run speedtest.net and pingtest.net to servers in the country the servers are located. for example if the server you play on is a USA server then a pingtest to UK will provide different results.
Test other servers from other countries: you can try connecting to mine - its dedicated and not home served so should have reliable connection based in the uk: /connect lilpwny.com
try other max_packet and rate settings - perhaps your internet cant handle these settings or ammount of updates from say 32 player server
try a server with less players? is the problem less intense?
try lowering graphics detail to see if this helps?
... just a few things I would try if i had the issue.
This post has been edited by NITRO: 18 April 2012 - 09:40 PM