Hardware Lister - lshw (Hardware Lister) is a small tool to provide detailed information on the hardware...
Psensor - Psensor is a graphical hardware temperature monitor for Linux.
iStat Menus - "An advanced Mac system monitor for your menubar."
HWiNFO - Professional System Information and Diagnostics. Comprehensive Hardware Analysis, Monitoring and Reporting for Windows and DOS. FREEWARE. download. Advertisements.
Speccy - Speccy - find the details of your computer's specs. Great for spotting issues or finding compatible upgrades. Download the latest version free.
Hardinfo - Hardinfo is a system information and benchmark tool for Linux.