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ATI Radeon Xpress 200P for Overclockers: Sapphire PURE Innovation PI-A9RX480 Mainboard Review (page 2)

Category: Mainboards

by Ilya Gavrichenkov

[ 09/02/2005 | 10:27 AM ]

ATI Radeon Xpress 200P for AMD Platform: Closer Look

Since NVIDIA nForce4 chipset turned into a sort of a reference for the AMD K8 platform, it is impossible to avoid comparing any new product against the solution from NVIDIA. This time is also not an exception: we perceive the ATI Radeon Xpress 200P as opposed to nForce4. And to tell the truth, its features don’t look that impressive against this powerful background.

First of all I would like to point out that ATI Radeon Xpress 200P is a chipset based on classical architecture, including the North and the South Bridge. While NVIDIA nForce4 proved the efficiency of the single-chip architecture for Athlon 64 platform, all other developers, including ATI continue to stick with the traditional dual-chip design. And I completely understand their motivation. When all the peripheral devices controllers are combined in a single isolated chip, the developer gets more flexibility for further chipset enhancement and fine tuning. By simply replacing one single core logic chip, they can enrich the chipset functionality and also add support for the new/different processors.

I would like to stress that this opportunity is very important for ATI. The company has always had some trouble with developing high-quality and feature-rich South Bridges. ATI replaces them with the new modifications much more frequently than the North Bridges, because of numerous improvements they introduce and small bugs they eliminate.

Moreover, there is a well-known PCI Express x2 bus with 1GB/s bandwidth connecting the chipset bridges in ATI Radeon Xpress 200P. By using this popular bus to connect the chipset bridges with one another, ATI automatically allows the use of South Bridges from other chipset developers. It is not a rare thing today that the mainboard developers would use ATI North Bridge together with a more functional South Bridge from ULi, for instance.

The North Bridge of ATI Radeon Xpress 200P chipset aka RX480 (the latest modification is called RX482) boasts a pretty common set of features typical of an Athlon 64 platform. It supports HyperTransport bus with up to 1GHz frequency connecting it with the system CPU and a PCI Express bus connecting it with the additional devices. ATI Radeon Xpress 200P North Bridge features 22 PCI Express lanes. Two of them are assigned for the connection with the South Bridge, four of them are responsible for PCI Express x1 slots. As a result there are 16 lanes left for the graphics interface, which can be used either by a single PCI Express x16 graphics bus or by two PCI Express x8 graphics buses simultaneously. The latter configuration is implemented in the Crossfire based systems with two graphics cards.