In 2005 we saw some evidence that nVidia was flattered by AMD’s
integrated memory controller as it made the job of chipset design
relatively easy. When nVidia adapted the nForce4 design to add SLI to
Pentium 4, the heat from the Northbridge had to be experienced to be
believed. Bolting on a memory controller to an existing chipset design
is, it seems, a serious undertaking. None the less, nVidia knocked out
some decent chipsets with nForce3 (Athlon 64 and AGP graphics) followed
by nForce4 with PCI Express.