Speccy - Speccy - find the details of your computer's specs. Great for spotting issues or finding compatible upgrades. Download the latest version free.
MSI Afterburner - Tool to manage video cards. Shows video card stats (temp, GPU usage, etc.).
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.
ASUS GPU Tweak - ASUS GPU Tweak fully implements TechPowerUp’s GPU-Z analysis and monitoring features.
AIDA64 - AIDA64 is a system information, diagnostics and benchmarking solution for Windows PC.
Guru3D - Guru of 3D: PC Hardware Reviews and tests