I want to upgrade ram. I have an Asus p2l97 motherboard with 3dimm slots. 2 are filled with 32 meg nonparity ram chips. Can I add mix memory? like keep those two and add a 64meg chip, or do they have to be same size? If I cant mix memory and cant reuse old memory, can I use PC100 memory? After I install new memory do I just have to reboot or do I have to change any jumper settings on motherboard or change bios settings in any way?