Sometimes it could be that bdss.exe (process that realtime protection uses to scan files and folders) uses lots of cpu usage that's due the realtime scanning of BitDefender virus shield. To reduce the usage you can try this open BitDefender go to antivirus,shield,adjusted level. Here you can exclude folders to do that click on don't scan this pad then browse to the folder that you would like to exclude then confirm it. You can also enable the option don't scan files larger then... (fill in a value). You have to confirm by pressing on ok after you changed the settings.

Hopefully it's helpfull.

Regards
Niels

I will add here things I experienced for reduceing bdss.exe CPU usage.

Open BitDefender go to antivirus-shield-custom level and under "Scan accessed files" choose "Scan program files only".

The other thing I found is when Remote Services service is disabled bdss.exe always use around 15% CPU, no matter if You are doing anything on the computer. Setting startup option for this service on Manual or Automatic resolves the problem. If this service is running then there is no need for intervention I mentioned in the first part of this post.

This will reduce the CPU usage, but it will also reduce protection against viruses that hide themselves as non-application files (like the recent ANI Exploit).
Personally, I prefere 1-2% CPU usage more instead of less protection.

I just had to $500 to replace my laptop's CPU because of bdss.exe. Yes, BD offers excellent protection against viruses and spyware. But the cure turned out to be just as bad as the sickness. I'll be going with something else now.

With respect, Satter, I doubt it was BD that harmed your CPU. I know of no software that can do that. Your CPU will have been damaged by overheating or was already living on borrowed time from previous mis-treatment or just plain old wear-and-tear. None of these are the fault of BD. Just a coincidence my friend. Your blaming BD is frankly ridiculous.

At Majorgeeks, Softpedia, etc., you can get the AnVir Task Manager Free. Install it, and use it to limit the bdss.exe CPU usage. This won't affect BitDefender's PC protection.

Hope this helps.

Dave

PS. Try deleting your internet cache, too; BD seems to distrust the internet junk.