Under the test, three consumer and three professional cards from AMD, as well as six comparable models from NVIDIA, were tested for 12 days of 24-hour stress testing using CRASH from the Microsoft Windows Hardware Lab Kit (HLK). No real-world games or professional rendering software were tested, so the results should be taken with a grain of salt.
Under the test conditions, QA Consultants found that AMD's video cards were more stable than those from NVIDIA. Surprisingly, consumer cards scored better than workstation parts. AMD GPUs passed 93 percent of tests, whereas NVIDIA products passed 82 percent.
You can check the full whitepaper over here (PDF).