DDR 400 RAM running as DDR320 in Dual Channel Mode

Hello,

I have the following PC Config :

Intel Pentium 2.8 Ghz Prescott ( I MB L2 Cache ) with HT
An Intel Original GBF Mobo ( with integrated Sound and graphics )
NVidia 5200 FX Graphics Card
A Sound Blaster Live 5.1 Sound Card
120 Gig HDD
512 MB DDR400 ( Hynix ) - 1 DIMM

So, I went and bought another memory module from Hynix, same config -
512 MB DDR400 and set it up in my motherboard in the Dual Channel
Config - Channel A Slot 0 and Channel B slot 0 as instructed on the
Intel Website ( I have 4 slots ).

A strange problem cropped up.
When I put the settings in Auto Mode in the bios, the bios recognizes
it as DDR320 ... and gives me Dual Channel ... but as DDR320
Both the modules work as DDR400 separately ...

So, I forced the settings to manual at 400 Mhz and they worked fine ...
even the benchmark tests jumped ...

But every other time, when I boot my computer, my computer goes on -
off like a voltage fluctuation during the boot and resets the RAM to
DDR320.

Why does this happen and what can I do ?
Any help would be deeply appreciated !
Thanks.

- Saurabh