Nvidia’s mobile graphics assortment  is a mix pot of last generation Fermi circuits and the new Kepler architecture. Today the new graphics cards GTX 675MX and GTX 670MX are unveiled as the sucessors to GTX 675M and GTX 670M. Confusing?

It is not easy to keep track of the models in the Nvidia Geforce 600M series for notebooks, especially the faster models. Nvidia has launched a new set of graphics cards for notebooks. The top segment has earlier been Fermi-based and renamed GTX 675M and GTX 670M, but this was before the launch of GTX 680M that uses the very latest architecture, Kepler. The two latest models add an X to the name GTX 675M and GTX 670M, but both are whole new graphics cards.

Model GTX 680M GTX 675MX GTX 670MX GTX 675M GTX 670M
Graphics circuit GK104 GK106 GF114
Graphics architecture Kepler Fermi
Node 28 nanometer 40 nanometer
CUDA cores 1 344 960 960 384 336
Texture units 112 80 80 64 56
ROP:s 32 32 24 32 24
Clock frequency 720 MHz 600 MHz 600 MHz 620 MHz 598 MHz
Shader frequency 1 240 MHz 1 196 MHz
GFLOPS 1 935 1 152 952 804
Memory bus 256-bit 192-bit 256-bit 192-bit
Memory frequency 3 600 MHz 2 800 MHz 3 000 MHz 3 000 MHz
Memory type 4 GB GDDR5 3 GB GDDR5 2 GB GDDR5 3 GB GDDR5
Memory bandwidth 115.2 GB/s 115.2 GB/s 67.2 GB/s 96 GB/s 72 GB/s

Both graphics card sports 80 texture units, 960 CUDA cores at 600 MHz and thus the same theoretic performance. The difference is that GTX 675MX builds on GK104 with 256-bit memory bus with 32 ROPs, while GTX 670M is based on GK106 and gets 192-bit memory bus with 24 ROPs. Besides fewer units and a narrower bus GTX 670MX gets slower memory, which results in much lwoer bandwidth than GTX 675MX and GTX 680M.

Both graphics cards should end up 15 – 20 percent faster than their siblings with the X, while consuming less power and emitting less heat. If they will replace these or not we don’t know, but we are guessing the old models will stick around for a while though. We will keep an eye out for these and try to get a notebook in for testing when possible.