This invention is directed to a system by which data received by an electronic device from a server may be selectively stored in cache. The electronic device may define an anchor that is related to the current position of a playhead reading data stored in cache. The electronic device may then dynamically assign values to each data block of the received file based on the position of the anchor. As the anchor moves, the value of data blocks changes, and new incoming data may replace less valuable data previously stored in cache.