s/iter  2**14  2**13  2**12  2**11  2**10
2**14    139     --   -78%   -97%   -99%  -100%
2**13   31.3   345%     --   -88%   -97%   -99%
2**12   3.88  3488%   706%     --   -78%   -95%
2**11  0.870 15902%  3493%   346%     --   -76%
2**10  0.210 66195% 14786%  1748%   314%     --