This entry is a user-made guide and not verified by any eMule developer, but is still a helpfull addition for most users. You you can find questions and comments on this topic in a dedicated thread on our forum.
Here are some tips to tweak eMule so that uses less resources.
1) Uncheck Show Splashscreen.
1) Slide the Progressbar Style to Flat.
2) Uncheck Show Transferrates on Title.
3) Uncheck Show download info on Catagory Tabs.
4) Check Disable Known Client List.
5) Check Disable Queuel List.
6) Check Don't Recreate Static Graph on Resize.
1) Uncheck Show Overhead Bandwidth.
2) Close all programs that are currently using your internet connection. Go to a site that can check your bandwidth and test your connection. For example, a DSL connection might get results like 1200 down/ 110 up.. Now, click on the wizard button. Select one of the three settings for Concurent Downloads. Then enter in the results of your bandwidth test into the True Download Bandwidth box and True Upload Bandwidth box. Press apply
1) Check Remove Dead Server After __ Retries. Also set the number of retires to 1.
1) Increase the delay times for the things you don't montor as much. (Graphs Update delay, Statistics Tree update delay).
2) If you don't use the graphs at all.. Slide the Graphs Update delay all the way to the left for disable.
3) If you don't use the statistics at all. Slide the Statistic Tree delay all the way to the left to disable them.
1) Uncheck Verbose(additional program feedback)
Number of files downloading
Also, try not to download a huge amount of files at once. eMule has to try to handle all these files and sources at once. This can also get you banned by some servers.
Be aware that software firewalls usually don't like P2P's. They were not intended to have to monitor the amount of traffic a P2P generates. Although ZoneAlarm is a great firewall, it can consume a lot of memory and hog your CPU (Or even freeze your system) trying to keep up.
Hope this helps some out there.. Good luck.
Warning: I will keep this thread open for discussion.. But most likely will update the main post periodically with the good information and corrections and delete the added posts to keep this thread clean.