The Secret of Second Generation ION Platform
Intel offered their Intel 945GC and 945GSE chipsets for us with the first generation Atom processors. the idea behind Nvidia ION platform implied that these chipsets had to be replaced with GeForce 9400 core logic set featuring a number of obvious advantages, two most important ones from the practical standpoint being much higher performance of the graphics core and hardware HD video decoding support. Replacing one chipset with another like that is easy – old Intel Atom processors from the Diamondville family use FSB system bus, which makes them compatible with any chipset designed for LGA775 form-factor.
However, Intel used a new approach to platform design in their new Atom processors from the Pineview generation. One of the major goals for launching Pineview was to increase the level of CPU integration, so that now the processor die also contains the major elements of the chipset North Bridge – graphics controller and memory controller. The Intel NM10 companion chip included into the same platform as Pineview has basically become a regular South Bridge, so in fact, there is no need for high-speed FSB bus anymore: the new Atom processors are connected to the chips via their proprietary DMI bus.
That is exactly why chipsets like Nvidia GeForce 9400 are no longer compatible with the new Intel Atom processors from the Pineview family. Moreover, there is no need for classical integrated chipsets, because the CPU has its own graphics core inside. However, in terms of performance and functionality this new graphics core is not that much different from the graphics in Intel 945GC or 945GSE. In fact, the differences include slightly higher clock frequency, which automatically means that there is no more or less acceptable 3D performance as well as hardware support for decoding of contemporary HD video formats. Therefore, it remains a very acute task to extend the GPU functionality and increase the graphics performance in the refreshed Intel platform. This is the task suitable for the new version of Nvidia ION.
Since Nvidia no longer can connect their chipset directly to the Atom processor, new generation ION platform which is also known as ION2 has very little in common with its predecessor. Since they couldn’t replace the Intel NM10 chipset with their own solution, the only way they could add their own graphics core to the new Intel Atom processor was by supplying Intel Pine Trail platform with an additional discrete graphics controller. So, while the first generation ION made Intel’s platform simpler by replacing two-chip core logic set with a single chip GeForce 9400, ION2 is an addition to Pine Trail: a new discrete graphics controller besides Intel NM10 chipset. In most cases it is GT218 chip – an integrated budget solution similar to Nvidia GeForce 210.
ION2 platform is also quite complex to implement because Intel NM10 chipset doesn’t have anything for connecting external graphics: it only supports PCI Express x1 interface version 1.0. So, GT218 graphics chip has to use this particular bus. However, Nvidia claims that ION2 platform has special optimizations in place that should minimize traffic between the CPU and the graphics controller, so the available data transfer means are more than enough.
In terms of architecture, GT218 chip doesn’t really offer any significant improvements compared with the integrated graphics employed in previous generation ION systems. Like GeForce 9400, it also has 16 shader processors and in some modifications designed for inexpensive netbooks, half of these processors may be disabled anyway. Of course, DirectX 10.1 compatibility as well as hardware video decoding acceleration are both there. However, unlike GeForce 9400, GT218 graphics processor requires its own DDR2 or DDR3 video memory connected along the 64 bit bus. The size of this memory may vary depending on a specific ION2 implementation, but may never exceed 512 MB. Proprietary video memory not only makes up for the insufficient bandwidth of the busses connecting the graphics chip with the processor, but also guarantees that ION2 platform will offer better graphics performance than its predecessor.
Overall, the graphics solution included with the ION2 platform has the following specifications: