The Ultimate Laptop Recomputed at a Finite Density Ceiling: A Disproof of the Planck-Density Figure

This paper examines what happens to the familiar ultimate-laptop figures when the Planck density is replaced by the finite Limit density. The calculation is performed in a frame with a finite maximum density, the neutron-branch value rho_A = 9.718e+57 kg per cubic metre, with the electron branch at 2.874e+51 kg per cubic metre for comparison. Headline results include a bounce temperature of 3.278e+22 K, a Landauer cost at that temperature of 3.137e-01 J per bit against 2.871e-21 J per bit at 300 K, a Bekenstein allowance of 1.049e+94 bits for the stated centimetre reference region, and a Margolus-Levitin rate of 2.209e+103 per second for the same region. The density replacement lowers the energy available to a fixed volume by the ratio of the limit density to the planck density, about 1.88e-39, and every derived rate falls with it. All numbers are computed from the stated assumptions in the accompanying script; the study is simulated and computed, not measured.