A few months ago now, NVIDIA launched the GeForce GTX 480M. It is however of limited interest in the mobile world given its enormous consumption levels and high pricing, which is somewhat out of step with the levels of performance it yields. Moreover Eurocom, who are selling laptops which include the card, sent out a communiqué a few days ago to remind users that although the GeForce GTX 480M is sold as an option, it isn’t of a great deal of interest as two Radeon Mobility HD 5870s in CrossFire draw similar power for much higher performance for $200 less than the NVIDIA solution. This situation was clear proof that it was time for NVIDIA to react and come out with some new mobile products. This they have now done with the GeForce 400M DirectX 11 range.
This range is based on new GPUs, the GF104 (already used in the GeForce GTX 460 for desktop), the GF106 (which will soon be introduced in the GeForce GTS 450) and the GF108. These GPUs use an improved architecture and are more effective in a gaming framework. To recap, this architecture is made up of GPCs (Graphic Processing Cluster) which includes a certain number of SMs (Streaming Multiprocessors) which themselves are made up of 48 processing units (the “cores”) and 8 texturing units. Here’s a general outline of these GPUs:
GF104: 2 GPCs * 4 SMs (384 processing units, 64 texturing units), 256-bit memory bus and 32 ROPs
GF106: 1 GPC * 4 SMs (192 processing units, 32 texturing units), 192-bit memory bus and 24 ROPs
GF108: 1 GPC * 2 SMs (96 processing units, 16 texturing units), 128-bit memory bus and 16 ROPs
Of course, these are the maximum specifications of these GPUs as NVIDIA can disactivate some of their processing units. Here first of all are the GeForce 400Ms based on the GF104 and on the GF106:
The GeForce GTX 470M is based on a GF104 with two SMs and part of its memory bus disactivated. Basically it’s a GeForce GTX 460 768 MB with 30% less processing power and memory bandwidth.
The GeForce GTX 460M and GT 445M usher in the GF106. In the first card, it’s used in the full version with 192 processing units and a 192-bit memory bus, which puts it, according to the rumours, at a level close to the forthcoming GeForce GTS 450 for desktop. Once again, we have to say that the significant difference between the specs of a desktop model and its mobile variant is to be regretted. This fools the consumer into thinking that they’ll be getting higher levels of performance than they actually do get.
The GeForce GT 445M is a more complex case. Its clocks have been revised downwards and it loses a block of processing units. Moreover, both 192-bit and 128-bit versions are on the agenda and with 800 MHz DDR3 or 625 MHz GDDR5 memory (1250 MHz for data). This means that memory bandwidth (and therefore perforance to a certain extent) could vary by a factor of two between two GeForce GT 445Ms of identical appearance. This sort of inconsistency will require extra vigilance to the details of your notebook on purchase, as long as these details are clearly displayed, which isn’t always the case.
In addition to these three new mobile graphics solutions, NVIDIA has launched 4 models based on its new entry level graphics card, the GF108:
The GeForce GT 435M, 425M and 420M are similar and only differ with respect to the GPU clock. They have similar specs to the GeForce GTS 360M, GTS 350M and GT 340M. The little GeForce GT 415M however loses half of its processing and texturing units. Basically it has a similar spec to the GeForce GT 325M. These new entry level solutions seem, then, on paper to offer similar performance levels to the old mid-range, adding DirectX 11 support in addition. Note however, the new architecture has certain limitations, notably when it comes to the fillrate which is likely to reduce yields in comparison to the older generation. Note also that NVIDIA says that the memory used with these GPUs is, at most, 800 MHz DDR3, which means that some solutions will be equipped with memory at lower clocks or even, still, that damned DDR2. And for the very low end, NVIDIA retains the GeForce 310M and 305M based on the GT218 and equipped with 16 processing units.
Overall, this DirectX 11 mobile range is a step forward for NVIDIA. Moreover, Optimus is an important advantage which allows you to use an integrated chipset and GPU pairing entirely transparently so as to reduce energy consumption at idle, a technology that AMD still hasn’t managed to respond to. Note however that energy consumption in load may be high. As NVIDIA has taken particular attention not to give us the TDPs for these solutions, we can only think they must be relatively high. According to one laptop manufacturer, the GeForce GTX 460M is at 70 watts, which should be set against the 50 watts drawn by the Mobility Radeon HD 5870.