I have a 64gb Sandisk Wireless Media Device or WMD. It is an SSD. How much free space do I need for it to perform properly and also the SDXC that I use in the slot, I am assuming the same rule would apply to both. When I get less than 10% free space the color of the SSD space bar onscreen goes from blue to red. The Sandisk tech support on the telephone said no minimum free space at all. I felt like he was clueless. Any input would be greatly appreciated