According to rumors going around in the Computer INternet community, the next GPU's being released by NVidia will be the 9900 GTX and the 9900GX2.
Now, nVidia just released the 9800GX2 and 9800GTX GPUs a few weeks before. So why would they keep releasing more and more new ones? Well, nVidia is releasing the 9900 series to replace the 9800 series. The 9900GTX will replace the 9800GTX, and the 9900GX2 will replace the 9800GX2. But again, why would they do this?
Frankly, I don't really know what the heck they're thinking. Doesn't that sound familiar though? That's the same thing they did for the 9800GTX; it was released to replace the former 8800GTX. So, why would they do the same thing twice? Well, a rather simple idea is that nVidia is stalling for more time. More time for what? To develop new chips of course!
Have you noticed that ever since the debut of the G92 chip in the 8800GT that they've been stalled in development? Here, look at their GPU's: the 8800GT, the 8800GTS G92, the 9600GT (G94, which is a close sibling of the G92), the 9800GX2 (just two G92 chips put together on a single card) and the 9800GTX (again, the G92 chip). They've been using the same chip for many months now. In my opinion, now would be the time for something new, something just so original that it just beats every other GPU.
If they keep this up, they may give ATi enough time to catch up on them in market shares, and maybe beat nVidia! Then no more part-monopoly! Who knows what will happen. But this will be a very interesting battle.