I know this has already been posted but they're are many different methods and I would like to share mine.
Here we go
1. Close all unnecessary background programs you may have going while playing CF
2. Make sure not hidden spyware/virus is using you're bandwidth instead of you
3. Get a better bandwidth connection
4. Go to task manger and you will see lots of processes in the processes tab, Close the unnecessary such as "DVDAgent" for an example
5. Use Game Booster if really low
6. Remove .Rez files
7. Play games with not a lot of people in them.
8. Run a virus scan before running CF
9. Plug directly into you're router.
Thank you for reading and I hope you find this useful