CIS 4 CPU resource hungry?

My games would stutter now and after closing the game I would notice that the CPU is used heavily.

Even when only firefox is running

One of the core always shows more than 50% loading. CIS 3.xx was so much lighter on the CPU load.
I ran diagnostics and CIS reported that installation was fine. However I may be forced to revert back to previous version as CIS 4 is too CPU demanding for me.

This taken with firefox opening two sites no download or anything and no other application opened.

Edit:
I’ve reverted back to ver 3.14. Version 4 was too heavy on the CPU load for me(Vista x64 system)
I have no virus or malware in my system that I know of and ran complete AV scan with CIS 4 updated AV database and it reported my PC as being clean.

Did you have the sandbox enabled? May be that contributed to the big extra CPU usage.