Tom's Hardware guide posted a review on the Nvidia GeForce GTX 260/280

Over a year and a half – that’s how long the GeForce 8800 GTX remained in the position of what could be called Nvidia’s high-end GPU. Oh of course, six months after its release and – just a coincidence – just before the arrival of the R600, we did get an 8800 Ultra with slightly higher clock speeds, but it was nothing revolutionary. Then two and a half months ago, the arrival of the 9800GTX awakened hopes of substantial performance increases, but in the end the card offered only limited gains over the good old GTX, and was behind the Ultra version. For owners of these cards to be really happy with their investment, it was high time for Nvidia to offer more than a few extra megahertz or to rely on pairing two GPUs on the same card.

Nvidia GeForce GTX 260/280 Review