Two question, one on RAM slot distribution (2x4gb vs 4x2gb), one on OC

[wannaturnuptheheat]

1st:

If I wanted to put 8 GB of RAM (yes, I edit videos) into my computer, would it be better to do 2x4GB sticks, or 4x2GB sticks?

2nd:

If my motherboard supports up to 1333MHZ DDR3, but the RAM's stock speed is 1600MHZ, how do I clock it up? And will it be dangerous/damaging to the RAM or motherboard?

EDIT: PSU is 650W, mobo is Gigabyte GA-890, and I plan to have two Radeon 6870s. More PSU, too?

 

[Zenthar]

1st: 2x4GB would be "better", but usually not in a perceivable way. Having less RAM modules usually allows for more aggressive clock speed and timing while keeping the voltage low. However the difference would not warrant spending more $$$.

2nd: If you just plug the RAM in, it will run at 1333Mhz so no danger for either the RAM or the MB. However, it also mean you could OC your RAM up to 1600Mhz without issue (unless from the MB).