ATI Radeon Xpress 200G reference board

Quite a tempting package?

Review ATI is something of an underdog in the chipset market and some of its early products had, shall we say, low appeal. However, with the introduction of the Radeon 9100 Pro IGP, ATI gained a lot of ground in the mobile market, writes Lars-Goran Nilsson.

ATI has shied away from AMD-oriented chipsets for a while, but the recent launch of the Radeon Xpress 200 chipset signalled a change of mind. It also marked ATI's first attempt at a PCI Express chipset. To be honest, ATI has managed to put together quite a tempting package for just about anyone considering an Athlon 64 or Sempron Socket 754 based machine.

ATI Radeon Xpress 200G

There are two different versions of the Xpress 200 chipset available: the P and the G (the one on review here). The P version doesn't feature the integrated graphics of the G and to be honest, this is no great loss as you'll see from our performance numbers. But since ATI makes graphics cards as well as chipsets, there's at least one scenario where the integrated graphics will come in handy and this is with ATI's SurroundView. This allows the integrated graphics to work in conjunction with a PCI Express graphics card and gives you the opportunity to use an additional monitor. If you're lucky enough to find a Radeon Xpress 200G motherboard with two outputs, you could possibly even use four monitors if you combine it with an ATI graphics card. Making things even easier is the fact that the Radeon Xpress 200G chipset uses the same drivers as ATI's Radeon graphics cards.

The motherboard ATI supplied for testing featured both D-SUB and DVI, but if we'll have to wait and see whether any motherboard manufacturers produce DVI equipped boards - but at least the support is there. One interesting feature that ATI has brought back from the dark ages of integrated graphics is on-board video memory, but with a twist. ATI refers to the integrated memory as SidePort and although I doubt we'll see it on any desktop motherboards, it's quite likely to appear on a lot of notebooks using the Radeon Xpress 200G chipset.

There are advantages and disadvantages to SidePort. The advantage in a notebook design being that it should improve battery life, especially in general Windows usage. This is because the integrated GPU can access its local memory rather than having to go via the CPU. This means that there will be less load on both the CPU and memory. It can also be combined with shared system memory and increase the overall performance, which is the best way to utilise it if you're playing games.

The downside is that ATI is only using a 32-bit bus for the SidePort memory, which isn't all that quick when you consider that the latest graphics cards use a 256-bit bus. This means that the performance will be quite lacklustre and even an X300SE graphics card would outperform it.

However, ATI has added another feature that none of the other integrated graphics manufacturers offer: the ability to change the allocated system memory share size in the drivers. This makes it far easier for the user to change the memory size on the fly, and it's ideal if you want to switch from say, photo editing to game playing.

The Radeon Xpress 200 chipsets supports 22 PCI Express lanes with 16 of these dedicated to the x16 PCI Express graphics slot, while four can be used to either provide expansion slots or on-board peripherals. Interestingly, the ATI SB400 South Bridge is connected to the North Bridge via two PCI Express lanes, something that is usually done over a proprietary bus, and which demonstrates one of the features PCI Express - then known an 3GIO - was originally designed for. Two PCI Express lanes should, however, provide more than enough bandwidth for the integrated devices in the SB400, as it doesn't feature integrated LAN.

What the SB400 does have on offer is native support for up to four Serial ATA 150 devices and four IDE devices, up to eight USB 2.0 ports and eight-channel AC97 audio. The SATA controller supports RAID 0 and 1, but not 0+1. Hopefully, ATI will bring out a south bridge with integrated high-end audio and Ethernet at a later stage, since these are features that one would expect from any up-to-date chipset.

The reference board that ATI supplied for testing featured a lot of extra connectors and sockets which are used for chipset validation and final production boards will look much cleaner. Several motherboard manufacturers are already preparing to launch products based on both versions of the chipset and some might even be available before Christmas.

Next page: Verdict