6. The Family Bands Of GeForce2Go

NVIDIA's low-cost Geforce2 MX is the 'big brother' of the Geforce2 Go chip. The memory interface of GeForce2 Go can be 32/64/128-bit wide and support SDRAM or DDR-SDRAM memory. There will be a big range from 8 MB/32-bit SDRAM to 32 MB/128-bit SDRAM solutions depending on the notebook maker. We already mentioned the strengths of GeForce2Go, which are fill rate and integrated T&L. This will most likely make this chip faster than Mobility RADEON in 3D-applications.

With the information I have at this time I would design my Geforce2 Go solution like this:

Most graphics cards use 2Mbit/32-bit memory chips. This enables the following memory configurations: 8 MB/32-bit, 16 MB/64-bit and 32 MB/128-bit. Other designs might be possible too. The 32 MB version will be a challenge to implement with 128-bit. The preferred solution will be a 32 MB/64bit DDR SDRAM. Both the core and the memory clock should be adjustable depending on the power status. A high clock setting would make sense when the notebook is using AC-power and a low clock setting when it's battery powered. The thermal problem can be tackled best by reducing the voltage. Every overclocker knows however, that higher clocks require higher voltages. Depending on the thermal envelope available in the notebook design the chip might have to run at a lower clock than theoretically possible. This graphics solution will require a lot of real estate inside the notebook and consume more power then NVIDIA is willing to admit. You need space not only for the graphics chip, but also for the memory nearby, and believe it or not, both will consume power. The power consumption of the memory chip(s) has to be added to the power consumption of GeForce2 Go in order to make it comparable to an ATi chip with integrated memory. 8 MB will add up to 0.25W to NVIDIA's power calculation.

Toshiba is NVIDIA's launch partner, using GeForce2 Go with a 16 MB 64bit DDR-SDRAM solution, running at 143MHz core clock and 166MHz memory clock. These Toshiba notebooks are still unavailable, so we were forced to simulate a GeForce2 Go as well. We used a 32 MB ASUS V7100 Geforce2 MX card and clocked it down to the above-mentioned frequencies of GeForce2 Go. This simulation is somewhat of a best-case scenario for GeForce2 Go, because it is using 32 MB of graphics memory. The peak memory bandwidth of the simulation is identical to the upcoming Toshiba solution. While the Asus V7100 card is using SDR-SDRAM at a 128-bit wide interface, the Toshiba notebook is supposed to run DDR-SDRAM on a 64-bit interface.