I've been told by G.Skill, that my RAM is actually optimized for Intel systems. Is this even possible?
By now, I'm also looking for new RAM, and would like to know if there are any brands or types that are AMD optimized?
It is possible. AMD and Intel have similar instruction sets for most operations. However, they each have their own 'optimised' instructions for doing particular things. Saying that their RAM is optimised for one chipset or another means that is supports these extended instruction sets. G.Skill makes RAM that works in both systems, though one model might work better in Intel systems while another model works better in AMD systems.
The best thing you can do is to look up what RAM is supported/recommended by your motherboard manufacturer. Check the documentation or manufacturers website for specific information.