VGChartz' William D'Angelo: "This chart compares aligned sales for the PlayStation 4 and Xbox combined versus the combined sales of the PlayStation 3 and Xbox 360. The PS3 and Xbox 360 both had slow starts, while the PS4 and Xbox One both had the two biggest launches in gaming history, which is reflected in the plotted line.
The gap has continued to grow for three straight months now in favor of the PlayStation 4 and Xbox One. The gap in the latest month grew by 13,913 units. The PlayStation 4 and Xbox One lead by a combined 13.37 million units.
The PlayStation 3 and Xbox 360 in their first 22 months sold a combined 25.96 million units, while the PlayStation 4 and Xbox One have sold a combined 39.32 million units.
Total Combined PlayStation 3 and Xbox 360 Sales: 25,957,125
Total Combined PlayStation 4 and Xbox One Sales: 39,328,552
Total Lead: 13,371,427 – PlayStation 4 and Xbox One"