Testing the Alienware notebooks with NVIDIA GeForce GTX 680Ms while seeing reviews for the GK104-based GeForce GTX 660 Ti and GK106-based GeForce GTX 660 go up has been interesting because it seemed as though NVIDIA's branding had painted themselves into a corner with the GTX 670M and 675M. Both of those chips are re-brands of last generation's Fermi-based GTX 570M and 580M, respectively. So while the GK106 would be seemingly ideal for notebooks, where was NVIDIA going to put it? The GTX 660M is based on GK107 with GDDR5, and then it's a jump to Fermi for the 670M.

As it turns out, NVIDIA's branding team is as creative as they've always been, although this launch is an unusually quiet one. No press releases or fanfare, but certainly worthy of attention. NVIDIA is updating their mobile line with the GTX 670MX and GTX 675MX, both of which are based on Kepler silicon.

The GTX 675MX, essentially replacing the GTX 675M, seems to be a full GK104 chip, with 960 CUDA cores and up to 4GB of GDDR5 on a 256-bit memory bus. Assuming the performance difference between the desktop GTX 660 and GTX 560 Ti (the two chips powering the GTX 675MX and GTX 675M/580M respectively) scales down, the 675MX should be about 20% faster than its predecessor. It's clocked at 600MHz on the cores and an effective 3.6GHz on the GDDR5. I'm not 100% sure on the GPU on this one, though; it'd have to be GK104 cut down to five SMX clusters, which would be accurate to the GK106 except for the 256-bit memory bus (GK106 only supports 192-bit).

Meanwhile, the GTX 670MX appears to be using a full GK106, as it too has 960 CUDA cores but only tops out at 3GB of GDDR5 on a 192-bit memory bus. It's clocked at 600MHz on the CUDA cores and 2.8GHz effective on the GDDR5. Again this should be a fairly handsome performance improvement over the Fermi-based GeForce GTX 670M.

As an added sidebar, NVIDIA has also launched their first Kepler-based Quadro mobile GPU, the Quadro K3000M. This appears to be a heavily cut down GK106, with 576 CUDA cores and up to 2GB of GDDR5, presumably on a 128-bit memory bus.

Origin PC was the first to get into our mailbox announcing immediate availability of these GPUs, but undoubtedly they will gradually become available from other vendors as well.

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  • iMacmatician - Sunday, October 14, 2012 - link

    According to the NVIDIA product comparison sheet, the Quadro K3000M has a 256-bit bus, which would point to it actually being a really heavily cut down (in terms of SMXes at least) GK104.

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