I need to make a Sawtooth last for the next 1 or 2 OS revisions. I've gotten to buying a video card (2x/4x version of the ATi 9800 Pro Mac Edition), and I need to put in more RAM. Here's the catch: the motherboard is unstable (hard crashes and freezes in OS 9, frequent KP's in X) with RAM in the second slot. Can I put RAM in only the 1st and 3rd slots, or do I need to fill them sequentially (and thus I should look to get a 1 GB DIMM)? Also, will a 1GB ECC registered DIMM work, or would I need to get non-ECC? For some reason ECC is much cheaper at that capacity in PC133 these days.