Meet the new Radeon
Published: 14 Aug 2001 16:53 BST
Until now, Nvidia's GeForce3 has been the only announced graphics hardware capable of delivering the stunning programmable pixel and vertex shader effects built into DirectX 8. ATI Technologies has now unveiled its competitive response to the GeForce3, a DirectX 8-ready successor to the popular Radeon graphics chip. Formerly referred to by its internal code name, R200, this new chip will power the Radeon 8500 -- the most potent gaming card of ATI's new autumn products. For those looking for the sweet spot between price and performance, ATI has also debuted a new mainstream product, the Radeon 7500, based on a higher-speed version of the original Radeon graphics core.
ATI has already revealed extensive details on two of the Radeon 8500's key technologies -- Truform and Smartshader -- but until now, the company has kept the meaty hardware specifications under wraps. At the grittiest level, R200 is composed of 60 million transistors (compared to the 30 million transistors in the original Radeon or the GeForce3's 57 million), produced using .15-micron process technology. One of the advantages of this smaller process is that it reduces heat output, allowing ATI to achieve higher operating frequencies. As such, the core of the Radeon 8500 will operate at 250MHz. The chip's 3D rendering engine boasts four pixel pipelines with six texture units per pipeline, delivering a maximum of 1 billion pixels per second or 6 billion textured pixels per second. Microsoft's upcoming DirectX 8.1 includes modifications to the pixel shader specification, which allows the Radeon 8500 to make use of up to six textures per pass on each pixel. It's the Radeon 8500's ability to do many simultaneous texture effects that has led John Carmack to predict that the new Doom graphics engine will perform twice as well on a Radeon 8500 as on a GeForce3. The revised API is set to launch at the time of Windows XP's release in October but may first arrive on the ATI driver disk.
The 275MHz DDR memory modules in the Radeon 8500 will be capable of providing 8.8GB per second of raw bandwidth, yet ATI predicts that effective throughput will hit up to 12GB per second thanks to second-generation HyperZ technology. Three major improvements have been made in the name of conserving bandwidth. First, Hierarchical Z, which minimises the number of unseen triangles rendered by the accelerator, has been enhanced to discard up to 64 pixels per clock cycle. According to ATI, this is eight times more effective than the original Radeon and four times the GeForce3's capabilities. Secondly, Hierarchical Z now operates on 4x4 blocks of pixels instead of 8x8 blocks, increasing the chance of detecting pixels that should be discarded. Finally, the algorithm responsible for compressing Z data (data associated with an object's depth in 3D space) has been further optimized, resulting in a total performance improvement of around 20 percent. With this extra bandwidth, demanding games should run smoother at higher resolutions and 32-bit colour.
To match the GeForce3's improved high-resolution antialiasing, ATI has developed a random sampling antialiasing procedure dubbed Smoothvision. Instead of the single fixed pattern in standard supersampling or Nvidia's five-sample Quincunx multisampling method, the Radeon 8500 is capable of a number of different quasi-random supersampling patterns. ATI's approach uses up to 16 samples per pixel in irregular patterns to better smooth diagonal edges that are hard to do with traditional square patterns, while avoiding the blurring effect that Nvidia's Quincunx method can cause. Simulators and other game genres that benefit heavily from antialiasing should be able to run smoother, with sharper clarity than ever before. ATI hasn't yet finalised how Smoothvision will work in the Radeon 8500 drivers, and it is still tweaking the settings to balance performance and image quality.
In addition to the 3D graphics enhancements, ATI has also improved its acclaimed video engine, known as Video Immersion II in its new form. For the first time in a PC, the Radeon 8500 will include a component video connector that can connect the card to an HDTV. This component output, which will likely come as an adapter for the DVI-I connector, will make high-quality progressive-scan DVD playback possible on a PC. A revised adaptive de-interlacing algorithm will further enhance DVD quality by eliminating vertical jumping artifacts.
The performance-enthusiast market makes up only 5 percent of overall graphics sales, so ATI doesn't expect the Radeon 8500 to be a top seller. Instead, ATI plans to debut the Radeon 7500 mainstream consumer card alongside its flagship Radeon 8500 to attract those more concerned with a balance of price and performance than cutting-edge features. Those who heard of the rumoured Radeon SE earlier this year may find the specifications of the Radeon 7500 somewhat familiar. Indeed, the 7500 is centered on the same core as the first-generation Radeon, meaning the 3D engine contains two pixel pipelines, each with three texture units.
The Radeon 7500 is designed to be very fast in the current crop of games. ATI has transitioned the core of the Radeon 7500 over to a .15-micron lithography process as well, which helps the chip to run at 270MHz. By borrowing the memory controller from the more powerful 8500, the Radeon 7500 is able to accept 64MB of 230MHz DDR memory, providing the 7500 with much more memory bandwidth than the original 64MB Radeon. ATI's own performance tests give the Radeon 7500 a frame rate advantage of 10 and 15 percent over the GeForce2 Pro in 3DMark 2001 and 3DWinBench 2000. However, the Radeon 7500 lacks the 8500's Truform and Smartshader features, and it can't handle DirectX 8 vertex or pixel shader effects in hardware. DirectX 8 can have vertex effects processed by the CPU, but this can slow things down. When games that use the full potential of DirectX 8 start to appear late this year and in 2002, cards that lack hardware shader features will age quickly.
What the Radeon 7500 lacks in future-proof performance it makes up for in display features. ATI has added the flexibility of the Radeon VE's display engine, which includes dual integrated DACs for connecting two analogue monitors, integrated support for DVI-I output, and an S-video output for gaming on a TV at up to 1024x768. The Radeon 7500 will include the Hydravision multimonitor software bundled with the Radeon VE, making it easier to customise the arrangement of windows on a desktop that spans two or more monitors, which in turn makes working in 2D applications more convenient.
Both the Radeon 8500 and 7500 are priced competitively against Nvidia's GeForce3 and GeForce2 Pro. At launch, expect the 8500 to retail for $399, while the 7500 will weigh in at a more affordable $199. The Radeon 7500 should hit store shelves in the middle of September, and the Radeon 8500 should ship a week or two later.
See the Hardware News Section for full coverage.
Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet news forum.
Let the editors know what you think in the Mailroom. And read other letters.
Did you find this article useful?
45 out of 62 people found this useful
- Share this article:
