I have that MoBo. 2 of them in fact. One is running Mushkin 2X1gig DDR2 800 and the other is running some off brand DDR2 667. Niether give me any problems. Tell me more about your ram. Are they matched? For matched sticks, you should populate the first two (yellow) slots first. This would yeild a duel channel mode.
Also, what CPU you using?