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AMD 780G Chipset: Flexible Radeon HD 3200 Graphics

AMD and Nvidia Platforms Do Battle
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Radeon HD 3200 Graphics for DirectX 10

The 780G northbridge features the Radeon HD3200 graphics unit, with its 40 stream processors and 500 MHz clock speed; the RV610 GPU, better known as the Radeon HD2400, was the inspiration. It’s a DirectX 10.0 part, supporting Shader Model 4.0 and OpenGL 2.0. As we found in our chipset review, the graphics unit can easily be overclocked to almost twice the normal clock speed, which provides a significant performance boost.

Yet this isn’t enough to move the 780G’s 3D graphics performance into an area in which it would be suitable for serious gaming, despite graphics performance that is significantly higher than the frame rates we’ve seen on AMD 690 chipsets.

Optional Video Memory is Useless

The integrated Radeon HD3200 graphics unit may be combined with up to 512 MB of discrete video memory, though motherboard makers typically don’t take advantage of this. Cost is the key issue in the integrated platforms market, and every item that isn’t really necessary increases cost and potentially decreases a manufacturer’s stand in the tough battle. AMD says that using dedicated memory results in a graphics performance benefit of 10-15%, which we believe isn’t worthwhile when looking at the overall performance level. Upgrading a Radeon HD3450 card may not turn a 780G system into a racer either, but the investment is much more noticeable than using discrete graphics memory on the integrated unit.

D-Sub, DVI-D, HDMI and Display Port Outputs

The plethora of output options is still unmatched, as Nvidia does not yet support Display Port, nor Dolby TrueHD or DTS-HD audio via HDMI 1.3. Both AMD and Nvidia offer two independent display controllers; one runs the analog D-Sub 15 connector and the other powers your favorite digital output. It’s not possible to use two digital outputs such as HDMI and DVI-D at the same time, but you may use the D-Sub output plus any of the digital options to run two displays.

Finally, it’s also possible to add video outputs by plugging in one or more discrete graphics cards. However, you must choose between using multiple displays running on the integrated and discrete graphics units, or putting the two units in Crossfire X mode to increase performance — it’s not possible to do both at the same time.

Hybrid Crossfire X Enabled Through the Driver

If you want to increase the graphics performance of the 780G chipset, you can do so by plugging a Radeon HD2400 or Radeon HD3450 card into the PCI Express slot. All you need to do to enable the hybrid multi-GPU mode is to check the appropriate box in ATI’s driver, and you are done. AMD currently does not support any faster cards running in Hybrid Crossfire X mode.