- Athlon 64 (940-pin) and Opteron require registered dimms.
- Athlon 64 (754-pin) doesn't require registered dimms.
Just a couple of notes:
1. Athlon 64 (940-pin) <b>IS</b> Opteron !!!
2. Athlon 64 (939-pin), which will be released sometime in Q1 2004 (and probably at the end of it), will not require registered DIMMS.