These results are from an old version so are out of date.
NGSPICE RESULTS (TRAN SIMULATION TIME)
Pre-layout style/pure digital circuits: model evaluation dominate, but NICSLU is still faster than SPARSE in NGSPICE
Post-layout style/large mixed circuits: sparse solver dominate, NICSLU is much faster than SPARSE and KLU in NGSPICE
Speedups for refactor+solve time