Dude, you may want to read up on some basic overclocking tipps before you launch right into running 2Ghz ram (yes, 2Ghz ram is an overclock. The CPU only supports 1600Mhz officially).
Generally you need to watch the POST screen (disable the logo post thingy) on whether it displays all your ram (should say 6.......k) after you changed the ram settings. If not, you need to tweak VTT and Vdimm settings. Generally for 2Ghz ram speed you'll need at least 1,37-1,39VTT depending on BCLK, ram, CPU, timings etc. Maybe more. Be advised that going over 1,4V VTT on air might be dangerous.

You can't just plug and play 2Ghz ram, not on this board and not on any other (actually on some you can, but they set VTT so high that they'll kill your CPU after a few weeks...)

I found the 0619 bios to work pretty well.