The desktop GTX 280 is based on GT200, while the mobile GTX 280M and 260M are based on G92b 55nm, which makes a huge difference. You cannot put GT200 in notebook, as the chip is extremely big and hot, but you can use the same name and hope that people will buy it, simply as this will be the fastest chip for notebooks.

The runner up GTX 260M is a slightly lower clocked version with a few less shaders and it runs at 550MHz. It comes with 112 shaders or Cuda processor cores, how Nvidia calls them today, and the shaders run at 1375MHz. The memory is the same as at GTX 280M and it runs at 950MHz and the chip uses 256 bit GDDR3, the whole 1GB of it.

The card is capable pumping 462 gigaflops and it supports CUDA, SLI, PhysX and Hybrid SLI. Some notebooks featuring this chip should debut next week at Cebit.