AMD's 790GX served with secret sauce for overclocking

Reykjavik (Iceland) – AMD introduced its 790GX chipset and refreshed the 790FX today. Reviews of 790GX motherboards have been published by the usual suspects but there is one trend that especially has caught our interest: AMD goes after extreme overclockability.

During this year’s Computex tradeshow, we first learned that AMD was preparing a new Southbridge chip with the goal to enable an improved overclocking experience on Phenom Black Edition processors. This new chip is now available as the SB750 model, which is offered as part of 790GX and 790FX motherboards.

According to AMD’s Sami Maekinen, the company’s chipset team focused on finding the optimal paths to synchronize a Phenom processor with the Northbridge (790FX, 790GX, 770) and the Southbridge (SB700, SB750) to create room for additional clock gains. A Phenom 9850BE can be overclocked to about 3.0 GHz on average, but AMD suggests that the chipset improvements should lift that limit to about 3.2 GHz simply by leveraging features provided by AMD’s Overclocking Tool (v2.1.2).

Keep in mind that Phenom BE processors use an unlocked multiplier, which means that it is easier to overclock the chip without pushing the HyperTransport link.

As far as the 790GX chipset is concerned, the integrated DirectX10-compliant GPU works at 500 MHz in 2D and 700 MHz in 3D mode. By increasing the voltage, users can take the GPU all the way to 1 GHz – and even beyond 1 GHz, if you have additional cooling resources available. A 30% gain in clock speed means that AMD has the fastest integrated GPU on the market. This overclocking capability was confirmed by colleagues at OCWorkbench.