What is the type of the memory DDR2 or DDR3, if you don't know how to know, you can use speccy (
http://www.piriform.com/speccy)
If you have DD3 memory, I suggest this motherboard:
http://nl.msi.com/product/mb/G41M-P28.html (G41M-P28)
2.1V Voltage is always better if the ram need it. (if it's write in the description of the memory, how many Volt you need to configure) because the memory is more stable. Never run the memory under the (1,8V)(or what the description say) it's decreased your performance.