techPowerUp GPU-Z displays information about graphic's card configuration and real-time situation of GPU load and memory usage.
This is a lightweight program which shows data about graphic card: name, technology, BIOS version, memory size, driver version, bus interface and more.
You can view real-time info about sensors: GPU and memory usage.
It includes a nice option to take and save a screenshot. Also, you can save log reports.
GPU-Z is available as free download for Windows 32-bit and 64-bit.