Installing Dual Channel DDR...

1.get cpuz from <A HREF="http://www.cpuid.com" target="_new">http://www.cpuid.com&lt;/A> to make sure

2.Try bank 2 and 4 instead

3.Consult your manual to find out about jumpers

4.B*tch at the support-crew  

Soltek SL-86SPE-L - P4A -2.4@2.766 - i865PE - 1024mb ddr400@307 w. TT A1165 - Ati Radeon 9700@381mhz 128Mb@626mhz - 600W dualfan(front/rear) PowerTek Psu - maxtor 4K080H4 & 6Y120P0 - samsung sm-352b

Ah ok   Awesome, it is under Dual mode.

Weird that Sisoft's Sandra didn't detect it, and neither did Asus's PC Probe utility.

heh... your welcome.. what's your sisoft-score?
You can also try Aida32--- amazing software with fast benchmarks

Soltek SL-86SPE-L - P4A -2.4@2.766 - i865PE - 1024mb ddr400@307 w. TT A1165 - Ati Radeon 9700@381mhz 128Mb@626mhz - 600W dualfan(front/rear) PowerTek Psu - maxtor 4K080H4 & 6Y120P0 - samsung sm-352b

You should see a mention about memory channel configuration in bold characters during POST (something like this : <b>Dual Channel Mode</b> or <b>Single Channel Mode</b>). Usually the board auto-detects the configuration. The Asus A7N8X DX has 3 memory slots. A slot 1-3 or slot 2-3 configuration enables Dual Channel Mode automatically. If you wish to fill your memory slots and still take advantage of the Dual Channel Mode, you need to insert the total amount of RAM of slots 1 and 2 into slot 3 (i.e., slot1 = 256Mb, slot2 = 256Mb, slot3 = 512Mb) preferably with similar timings.

<font color=red>That was my two cents!</font color=red>
<font color=blue>Now I'm broke!</font color=blue>