Can anyone tell me what the difference is between these two chipsets? SIS655 and SIS693? I've searched around and so far I've been able to find that 655 is Northbridge(?) and 693 is Southbridge(?). I have NO idea what this means. I'm actually trying to determine if I'm going to experience any problems when I put my computer back together. I had a defective Asus M/B (P4SDX) w/SIS655 chipset and sent it back to Asus. They replaced it but I just went to install it and realized that the new one has an SIS693 chipset and not the 655 I originally had. Can't find a way to contact SIS and Asus takes forever to answer any questions. So, was this an OK switch or do I need to go back to Asus? Will I have to do anything different because of the different chipset? As you can see, I'm totally ignorant about this and Asus didn't even tell me they had switched chipsets, much less anything about it! Thanks for any advice.