Introduction
ASUS Extreme EN5900/TVD (PCX5900) PCI-Express 128MB and ASUS Extreme AX600XT/HTVD PCI-Express 128MB Graphics CardsPCI Express is the buzzword in the graphics card industry right now. It kind of makes implicit sense, too. Before PCI Express (PCIe), the preferred protocol for transferring data to and from a graphics card was AGP (Accelerated Graphics Port). Its 32-bit-wide data bus is pegged at 66MHz. A bit of simple maths and you'll discover that standard AGP has a transfer rate of 264MB/s ((32x66)/8). Current protocol speed is up to 8X standard, or around 2.1GB/s bandwidth. That's fine and well for older games but newer titles utilise massive texture data that will, in a while, begin to swamp the bus' bandwidth ability. Not only that, the PCIe protocol ensures that bandwidth is reserved when needed, HDTV, for example.
That's where PCI Express comes in. PCIe slots reserved for graphics cards operate at what's termed X16 speed. That's effectively 16x the base PCIe bi-directional 500MHz frequency, or 8GB/s. On a far more practical and immediate level, Intel's new 900-series of performance chipsets generally use PCI Express for graphics communication duties. PCIe is both needed and more elegant than the incumbent AGP protocol.
That's why you'll undoubtedly be reading about PCIe graphics cards for the next few months. Both big-time players, NVIDIA and ATI, have PCIe designs to complement their AGP-driven models. That's why I was only too keen to take a look at a couple of ASUS' PCIe cards that don't break the bank yet offer decent performance.
