Urgent help

[dynasty]

hi
I have gigabyte 945pls3 mobo , and before i had 2x512mb bus533 geil ram on my system(dual channel) recently i change my rams to 2x1gb bus800 crusial bullestix.. but i have a graet problem,, when i use one of them ,i mean only 1gb from single channel there is no problem, but when i install both of them from dual channel ,system starts and windows also boots but in this case i have about 1gb capacity reduction from my windows(C) drive.
i dont know what should i do?
but i have good performance in games...
please help
thanks

 

[Tmagic650]

Motherboard spec says DDR2 533 only, 2GB max. You can buy 2 more DDR2 533MHz 512MB modules, or 2 1GB 533Mhz modules. Return the 800MHz modules. Always check the motherboard specs before upgrading RAM