Hello gregevan. Not to replace the excellent help of Frederik, but I have some advice to offer.
- Update your BIOS(as already stated) as it is a few revisions old. BIOS updates often address stability issues. ASUS - Motherboards- ASUS P6T SE
- Update your ASUS Drivers, including AI Suite, they can be found in the above link.
- Overclocking? I believe so. This BugCheck code in conjunction with overclocking, can be a result of too low of VCore. If you are(which I am fairly certain you are) overclocking, please stop for now. We need to test stability before you revert back to an overclocked state. EDIT: yes, to confirm, you are overclocked. To a whopping 4ghz!