A method for managing garbage collection in a memory subsystem, where a stream data manager writes data units from a stream of data into an allocated portion of memory composed of a plurality of blocks. The stream data manager evaluates a behavior of the stream of data to calculate the stream's efficiency, the behavior including amounts of valid data units from the stream of data in the allocated portion of memory. The stream data manager estimates a number of block stripe fills until an amount of valid data units is predicted to be within a predetermined range of a threshold value of valid data units in the block using the evaluated behavior. The stream data manager performs the estimated number of block stripe fills. The stream data manager performs the garbage collection of a first block of the plurality of blocks in response to performance of the estimated number of block stripe fills.