Nvidia transforms switchable graphics with Optimus

GRAPHICS OUTFIT Nvidia has thrown back the curtain on Optimus, a system that allows for the dynamic switching of graphics systems on notebooks.

Today's laptops usually have to suffer a trade-off between Intel's subpar but energy efficient integrated graphics processor (IGP) or a higher performance but power-hungry discrete graphics card that mounts a GPU from a graphics vendor like Nvidia or ATI.

Some vendors have attempted to strike a balance by creating a switchable graphics platform that allows the user to opt for which card they'd like to handle the graphics. Over time the switching process has developed from an actual physical switch, which required the machine to be shut down in order to move from one to the other, to a software switch that, in some cases, can be done while the operating system is running. However it's remained a manual process that usually requires at least a few seconds and a lot of screen flickering as the computer switches from one graphics subsystem to the other.

As a result, analyst Roger Kay from Endpoint Technology Associates reckons that only about one per cent of users who have a switchable graphics setup ever actually transition from one mode to the other.

"Switchable graphics is a great idea in theory, but in practice people rarely switch," he said.

"The process is just too cumbersome and confusing. Some buyers wonder why their performance is so poor when they think the discrete GPU is active, but, unknown to them, it isn't."

Nvidia reckons that Optimus changes all this as it allows the computer to seamlessly and automatically switch between the discrete and integrated graphics chips depending on what applications are running, or in some cases what features are used.

Current switchable graphics systems feed both chips into a MUX which then controls which one is providing the display and controls the graphics drivers for that operating system. Optimus takes a different approach by instead treating the GPU like a co-processor and routing the discrete graphics feed through the IGP. When the discrete graphics power is needed, the GPU renders the image and then places it in the frame buffer, effectively overwriting the poorer image created by the IGP. This approach means that the operating system can almost instantly switch between the two graphics processors with no graphical interference apparent to the user.

Optimus is designed to be application aware, so that the GPU is instantly fired up whenever a graphics intensive application is loaded. However it can also be turned on by specific DirectX imaging and video apps that may only occasionally require the grunt of the GPU.

Optimus is designed to run on Nvidia's next-gen Ion and Geforce M products as well the Green Goblin's upcoming Geforce 200M and 300M GPUs. It will work in conjunction with Intel's Arrandale Core i3, Core i5 and Core i7 processors as well as with its Penryn Core 2 Duo and Pine Trail Atom N4xx chips.

The company has said that several manufacturers are putting Optimus into their products, the first being Asus with its UL50Vf laptop. µ