Is there a soft that will write/register daily core usage of my cpu? So I could see how much do I use 4 cores, do I sue all of them, or maybe just for couple of hours during the day all cores are actually used etc.
Have you looked at Aida64? I have a paid version and while I haven't specifically checked if it can do this, is does have logging functions. I think a 30 day free trial is available http://www.aida64.com/downloads
I think you have to enable them AIDA64 / main menu / File / Preferences / Hardware Monitoring / Logging Will have a look when I get home.
Afterburner seems to do it if your already using it. Make sure you allow a big enough MB limit if you want to monitor for say 24 hours.
Another option is HWiNFO which has a manual start/stop logging facility and saves to csv format (for use in a spreadsheet). It also offers an automatic logging option with a user provided hotkey and is free for non-commercial use. One minute of logging time creates a file of about 30 KB, so circa 1.8 MB per hour. http://www.hwinfo.com/
AIDA did the job, I need to upload it to Access and calculate for how long does it use all cores tc. to see if I really need quad core..