memory Upgrade

[Tom__]

Motherboard: Asus M2N-SLI Deluxe
Manufacturer: Mesh
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4600+
Memory: 2x 512 Mb OCZ 7200 5 4 4 15
Win XP Home SP2

I have purchuased 2x 1GB OCZ Platinum 6400 4 4 4 15 memory but it just would not work. The computer keeps restarting even with the 2 new memory moduls installed on its own.
Is it possible that the manufacturer overclocked the motherboard so that it would take the PC 7200 memory, although it is only designed for PC6400!?
If it did overclock it where and what should I look out for, what changes I have to make in the BIOS in order to accept the new memory moduls and is it possible to mix the two different memory (pc7200 - pc6400) ?

please advise
many thanks
(new to overclocking)

 

[steve258]

Maybe you just need to up the voltage a little now you have 4 sticks of ram, the 2Gb Platinum PC6400 can take upto 2.1V.

In ASUS motherboards all oc settings are in "Jumper Free Configuration" and in there look for DRAM voltage and DRAM frequency.