Now in windows, I use NForce ClockGenerator to increase my vcore further to
1.66v by changing the VID from 1.475v to 1.550v.

You can get the program
here.

Much thanks to Franck for his wonderful softwares.

 Extreme Overclocking w/ ASUS A8N SLI

This is the A64 tweaks I used:

 Extreme Overclocking w/ ASUS A8N SLI

 Extreme Overclocking w/ ASUS A8N SLI

I made a 3.2 Ghz screenshot with the 3800+ Newcastle but can’t bench with it.

 Extreme Overclocking w/ ASUS A8N SLI

I use Rivatuner to force my cards to run at 3D speed all the time to bypass
throttling.

 Extreme Overclocking w/ ASUS A8N SLI

The option marked in red shows where you can set the card to force the 3D speed
all the time.

I will try to modify for more vcore when I have to switch out the CPU.

For those who are adventurous, you can try soldering dipswitches to the VID
pins to try for higher Vcore. The VID Pins connections can be found here:

 Extreme Overclocking w/ ASUS A8N SLI

Update: Voltage mods for the board can be found here.

Now that I’ve shared my experience, I hope that new discoveries with regards
to this configuration can be shared
here.