The Multi-GPU index is a portable set of data that we assign to determine the multi-gpu potential of any motherboard. A higher index number indicates a favorable condition for multiple graphics cards while a lower number indicates a hindrance in one of our leading indicators. Since the Index does not take into consideration system architecture it can be applied to motherboards regardless of processor or chipset generations.
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips