[SOLVED] can i use ram 4gb + 2gb 800mhz om g41d3+ ver 6.3

Solution
If you mean one of each only 4GB would be in dual channel mode and the other 2 GB would be in slower single channel mode.
The RAM takes turns if they're both the same size. That can run up to DDR3 1333 RAM.
What CPU nad video do you have?