I just got a MSI 5850 the Twin Froz II model. It crashed in 3D mode after 30 sec - 1½ minuttes... . There are a lot of forum posts on crashing issues with AMD 5XXX series and not that many solutions, where people get it to work. I had the 3D problem - Some have it in 2D as well.
- Lowered the GPU to minimal in ATI overdrive. All crashes stopped
- Found sweet spot at 700 Mhz
- Installed the MSI afterburner, where GPU voltage can be modified
- Changed GPU voltage from 1,090 V to 1,125 V
- Result: Stable computer again. Have just run 3Dmark06, Vantage and Dirt 2 stress test without problems. Temp at 61 degrees C
Though I am still thinking about RMA. The GPU simply must be faulty, when it is not able to run at the specified 725 Mhz. Furthermore the MSI model is know to have great OC potential - Not this one...