It is pretty much supply constrained. Just look at the graph: http://www.vgcharts.org/aconscomps.php?name1=PS3&name2=X360&type=0&align=0 The big blue spike in December is where Sony shipped more PS3s than MS had shipped 360s. Both were impossible to find during that time period. According to vgcharts, the 360 sold 1,117,000 units in its 4 months. The PS3 sold 1,160,500 in its first 4 months. The difference between those two figures is 43,500 units. In order for Sony to maintain its "lead", if you want to call it that, they have to move 170,250 units in March. They moved significantly less than that number in February.