I suspect that the memory timings in your BIOS setup are incorrect.
Google for "memory timings"
Here are some links for you:
http://forums.amd.com/index.php?showtopic=12017
http://www.techpowerup.com/articles/...AMD/memory/131
http://www.pcstats.com/articleview.cfm?articleID=873
http://www.anandtech.com/memory/showdoc.html?i=2019
Getting these timings correct is one of the keys to a stable system. All too often crashes are blamed on the OS or the application when it isn't that at all.
