I gained more stability with the Chipset voltage mod. Here are some of the
results.

348 Mhz HTT with memory at 260 Mhz Cas 2.0, 2, 2, 5.

 Asus A8N SLI Voltage mods

 

 

260Mhz 1:1 at Cas 1.5, 2, 2, 0.

 Asus A8N SLI Voltage mods

 

 

282Mhz 1:1 at Cas 2.5 , 4, 3, 0.

 Asus A8N SLI Voltage mods

 

 

A nice SuperPi 1M (Unpatched) of 28 seconds with 3800+ New Castle:

 Asus A8N SLI Voltage mods