Some boards act funny with certain configs of RAM. @ sticks may be fine if they are SS but not DS. 4 sticks will work fine but 3 wont. Just examples, not quoting anything.
Intel P4 550(3.4)<font color=red>@4.2 posted 4.8</font color=red>
Ballistix PC2 5300@<font color=red>DDR2 780</font color=red>
ATI Radeon X800XL <font color=red>459/609</font color=red>
TT 680W PSU