Core Temp is one of the FREE software i was searching for which is a great , small size program of just 172 KB , which doesn't slow your PC to Monitor CPU temperature.
The uniqueness of it is that it shows the temperature of each individual core in each processor in your system! You can see in real time how the CPU temperature varies when you load your CPU.The temperature readings seem to be very accurate as the data is collected from a Digital Thermal Sensor (or DTS) which is located in each individual processing core, near the hottest part.
It's also completely motherboard independent very compact . It is a tiny but extremely powerful and accurate software and can be easily installed on both Windows Vista and Windows XP also Windows 7 ( x86 and x64 ).