NVIDIA GeForce 9800M GT SLI vs NVIDIA GeForce 9800M GT

NVIDIA GeForce 9800M GT SLI

The Nvidia GeForce 9800M GT is based on the G92 architecture and is essentially a reduced 9800M GTX chip with only 96 shaders instead of the usual 112 found on GTX chips. Like with the 8800M GTX, the chip is produced in a 65nm fabrication process and even share comparable specs. Since this is an SLI system, the amount of available shaders is doubled due to the use of two 9800M GT cards. Note, however, that the available memory is not doubled because the same content is stored onto each card.

Like all DirectX 10 graphic cards, the GeForce 9800M GT SLI contains "Unified Shader" cores, 2x96 stream processors to be exact. These cores take the place of dedicated pixel and vertex shaders and are even clocked higher than the core GPU itself.

Hybrid Power is a Windows Vista only option that allows switching between onboard graphics (with Nvidia chipset) and dedicated graphics cards, in this case the 9800M GT SLI. Therefore, the dedicated graphics card can be disabled at will for power-saving purposes. Future Nvidia cards are expected to allow automatic switching through drivers, now known as Optimus Technology. GeforceBoost does not work with the 9800M GT because the connection with the SLI chipset would not result in any increase in performance.

The performance increase of two 9800M GT cards in SLI mode is between 0% and 40% over a single 9800M GT, depending on the application. For current DirectX 10 games such as Crysis, World in Conflict, Bioshock or Age of Conan, the performance of dual 9800M GT cards should be sufficient for smooth play at high levels of detail.

The phenomenon known as micro stuttering can occur in all SLI systems, including this 9800M GT SLI setup. The user may experience stutterings despite average frame rates of around 30fps. See here for more information on micro stuttering.

A hardware feature of the GeForce 9000 series is the integrated PureVideo HD video decoder. This allows the GPU to aid the CPU in decoding H.264-, VC-1-, MPEG2- or WMV9 video files.

The high current consumption of up to 130 Watt (when including both the VRAM and MXM board) means that the 9800M GT SLI is reserved for large and heavy laptops with sufficient cooling only. Therefore, the 9800M SLI series can only be found in big and heavy laptops.

NVIDIA GeForce 9800M GT

The Nvidia GeForce 9800M GT is a graphics adapter for laptops and is based on the  9800M GTX (G92 core), but with only 96 shaders instead of the 112. The 9800M GT is produced in 65 nm and is therefore more similar to the 8800M GTX as both cores have similar shader counts. The chip is intended for relatively large desktop replacement laptops with more powerful cooling. 

Similar to all cards with DirectX 10 capabilities, the GeForce 9800M GT renders 3D images using "Unified Shaders". There no longer exists any dedicated pixel- and vertex shaders. Instead, 96 so-called stream processors handle most of the the graphics work previously done by vertex and pixel shaders. Furthermore, these shader units are clocked higher than the core GPU processor.

The performance of the 9800M GT is similar to the Geforce 8800M GTX (same specs). The GTS 360M with GDDR5 and the 9800M GTS both with higher clock speeds) also perform on the same level as the 9800M GT. Therefore, the performance of the 9800M GT in 2008 and 2009 was sufficient for most games in high details. A detailed performance analysis of the 9800M GT can be found in our 9800M GT review.

An advantage of the GeForce 9000 series is the integrated PureVideo HD video processor. The GPU can assist the CPU in decoding  H.264-, VC-1-, MPEG2- and WMV9 videos.

In conjunction with the Nvidia 9100M G integrated graphics, the 9800M GT supports Hybrid-SLI in the form of HybridPower. HybridPower is a Windows Vista-only technique to switch between the integrated and dedicated graphics core for power-saving purposes. Up to now, the user had to use a tool to switch between the GPUs. Eventually, graphics switching can be done automatically in drivers (now known as Nvidia Optimus). GeForceBoost is not supported with this card as there would be no performance gain from combining the integrated GPU with the 9800M GT.

Compared to desktop graphic cards, the 9800M GT is most similar to the GeForce 8800 GS. The latter, however, still features higher memory clock rates and has a slight edge over the 9800M GT.