CPU Grab Ex is a freeware CPU stress testing application that's efficient.
Here are some screenshots to illustrate the features and user interface of this application:
Stress CPU (central processing unit) for testing. Screenshot of CPU Grab Ex - 2075px · 1721pxKeep an eye on CPU usage. Screenshot of CPU Grab Ex - 2075px · 1721pxDetect and prevent potential hardware failures. Screenshot of CPU Grab Ex - 2075px · 1721px