[SOLVED] ram voltage compatibility

[MehranD]

Hi friends
I've recently bought two pair of Kingston 4 GB 1333 ddr3 1.5-volt rams and already I had 2 pairs of Corsair 2 GB 1333 1.65-volt rams.
I changed the MB voltage setup to the default and it shows 1.5-volts for voltage of the rams.
I lowered the rams' speed to 800 MHz in order to prevent conflict of the provided voltage.
My question: Does lowering the speed really help? or I can set the speed to the default and use maximum ram speed?
My MB is Asus p7p55d and my CPU is intel core i3 530.
I'm not professional in the computer world (but so interested!) and I will really really appreciate your help,
and excuse me if my English is not good.

 

[CountMike]

They can all work at 1.65v and more.

 

[MehranD]

Thank you for answering
I had bought two pair of 1.5-v Kingston from store before these and because of a sudden I set 1.65-v for them for their first use but thay didn't work and finally I changed them.
Now I'm a bit concerned of loosing them.
What If I don't want to over-voltage them ? does it make problem for me ?