How many workers does your browser really give you? The root moves of a position are shared out between 1, 2, 4, 8 and 16 workers in turn, each worker searching its moves to the chosen depth, as on the parallel page. The wall time for each run gives the total nodes per second and the speedup over one worker, plotted against the ideal. The curve flattens when the workers outnumber the cores the browser will run at once, and a little before that because the root moves are not equal work, so a few slow moves at the end leave the other workers idle. Browsers report a core count which is shown for comparison.