Unable to Boot when adding two Hyper X 512

I have the DFI Lanparty NF4 Ultra. I have been using two Hyper X 512 sticks in the first dimm slots with no problem for over a year. Have previously had the voltage at 3.0 v. When I try and add another two Hyper X 512 sticks in the remaining two slots the PC will not boot and/or will boot to the logo screen and freeze?

What am I missing. No matter the configuration of 4 sticks of ram when I add ram in the second slots PC will not boot.

I have had similar problems running 4x512. It doesn't work very well in the Lanparty boards. Are the sticks identical? Same chips, SPD timings, etc. . ?
I had one hell of a time getting 4x512 Mushkin BH-5 to boot. I had to dump the SPD and reflash the sticks so they had identical SPD's. Even then, it shot my oc to hell. I finally broke down and bought 2x1gb.

So I updated the bios with the latest revision and after some heart stopping issues. I am able to use all 4 slots with ram.

Should work fine then. Nice job.