The computational time and memory of three-dimensional (3-D) capacitance extraction have been greatly reduced by using a quasi-multiple medium (QMM) technology, because it enlarges the matrix sparsity produced by the direct boundary element method (BEM). In this paper, an approach to automatically determining the QMM cutting pair number and a preconditioning technique are proposed to enhance the QMM-based capacitance extraction. With these two enhancements, the capacitance extraction can achieve much higher speed and adaptability. Experimental results show over 10X speed-up and memory saving over the multipole approach with comparable accuracy.