GPU - MSI Afterburner: http://event.msi.com/vga/afterburner/download.htm
CPU - Realtemp: http://www.techpowerup.com/realtemp/
MISC - HWINFO64: http://www.hwinfo.com/download64.html
CPU: Prime95: http://files.extremeoverclocking.com/file.php?f=103
Only thing accurate for voltage readings is a digital multi meter. Any software will be inaccurate. I also wouldn't run programs like OCCT, furmark, intel burn test either since their load is unrealistic and most hardware will just throttle in it anyways.