DFI LP nF4 SLI-D Wired memory slots

I have new PC based on DFI LAn Party SLI-D motherboard. It seems that it has wired memory slots arhitecture- 4 memory slots. 1&2, 2&4 like A and B channels.
I have two single Kingston 512MB DDR400 CL.2 184-Pin DIMM moduls.
The wired think is that those two memory moduls running well just when they are in slot 2&4. If i give one modul in slot 4 computer just beepp-s and i cant start nothing even bios. When i plug memory modul in slot 2 it works fine. I have tested both single mem-stick on slot 2 with PCMark 2005 mem-test, and they passed it. When i trying run mem-test with both mem-moduls at once, in 2 and 4 mem-slot my system crashes (memory dump-blue screen, with some error message??), i dont know exactly what it says. I think something about non paged area and some adress numbers. All other application and games running fine without problems.Also in windows both memorys are recognized as 1GB DDR memory. I just want to know WTF is going on? Is there PC MArk2005 bug, or my mem-slot(s) doesnt works properly or is it just another wired manufacturer solution.
Any information is welcome.
Thank you