Are Open-Source GPU Drivers Sufficient For 4K Linux Gaming?

Last week I published the results of a 15-way AMD/NVIDIA GPU comparison for 4K Linux gaming that was centered around the proprietary AMD/NVIDIA graphics drivers. However, if you stick to using open-source Mesa/Gallium3D drivers and are a Linux gamer, here are some benchmark results comparing the open to closed-source driver performance at 3840 x 2160.