The standard picture of CV secular evolution predicts a spike in the CV distribution near the observed short–period cutoff P _ { 0 } \simeq 78 min , which is not observed . We show that an intrinsic spread in minimum ( ‘ bounce ’ ) periods P _ { b } resulting from a genuine difference in some parameter controlling the evolution can remove the spike without smearing the sharpness of the cutoff . The most probable second parameter is different admixtures of magnetic stellar wind braking ( at up to 5 times the GR rate ) in a small tail of systems , perhaps implying that the donor magnetic field strength at formation is a second parameter specifying CV evolution . We suggest that magnetic braking resumes below the gap with a wide range , being well below the GR rate in most CVs , but significantly above it in a small tail .