The percentage of ads filled in return of ad requests in other words the fill rate refers to the number of pixels the video card can create or write to memory per second. It is measured in megapixels or gigapixels per second, which is obtained by multiplying the clock frequency of the graphics processing unit (GPU) by the number of scan operations (ROP). GPUs with higher fill rates can display video at higher resolutions and frame rates than GPUs with lower fill rates.
There is no standard for calculating and reporting the fill rate, so companies have come up with their own calculation method. Some multiply the clock frequency by the number of texture units, others multiply the frequency by the number of pixel pipelines. Whatever the method, the calculation produces a theoretical value that may or may not be fully representative of real-world performance.
Fill rate is a GPU performance rating that corresponds to its ability to render pixels and produce high-quality video. Actual occupancy depends on many factors, including other system hardware and even drivers. Fill rate has been used as a performance indicator in the past, but performance indicators change as GPU technology changes.
The complexity of a scene can be increased by drawing one object on top of another and pulling back the pixels that cover it. This complexity is a waste because one of the objects is hidden from view. When the scene is more complex than the fill rate can handle, the frame rate will drop, causing the visuals to be cut off.