GPUs have loads of memory bandwidth. I can&#x27;t imagine a framebuffer taking more than a few microseconds to clear.<p>For example, Nvidia claims that the GTX 980 has a memory bandwidth of 223 GB&#x2F;s. (1920 * 1080 * 3)&#x2F;223e9 = 27us. Clearing all 4GB of VRAM would take 4&#x2F;223 = 18ms. This would have a negligible impact on user experience in most cases.<p>I guess the driver could also erase memory in the background as soon as it is deallocated, with zero user impact.