Prime95 - Prime95 is a program that searches for new Mersenne prime numbers.
CPU-Z - CPU-Z is a freeware that gathers information on some of the main devices of your system : Processor name and number, codename, process, package, cache levels.
System Stability Tester - System Stability Tester - Test your system's stability and performance by calculating millions of digits of Pi.
Speccy - Speccy - find the details of your computer's specs. Great for spotting issues or finding compatible upgrades. Download the latest version free.
CPU Frequency Selector - Cinnamon CPU Frequency Selector Applet
AIDA64 - AIDA64 is a system information, diagnostics and benchmarking solution for Windows PC.