With Intel Bad Axe 2 MB and fully populated RAM banks...

With AMD, if you fully populate the Memory banks with ddr 400 ram you throttle back to ddr 333 usually. I haven't built an intel system in 10years... So if I buy only 2GB now and later decide that I want 4GB and add 2 more 1GB sticks will this cause my headaches? I want to run ddr2 800 on all four sticks is this going to be possible. Thanks