All the red "covers" are heatsinks and yes they are needed for heat dissipation. The heatsink right behind the SATA ports, if that is the one you are talking about actually is a large metal covering a very small chip. You can take it out and look, it's screws from the bottom. That also means you can trim it down a bit to fit your GPU, but of course once you do that, Mobo warranty is void. Another option is to buy a third party heatsink that serves you better.