It is no secret that for a long period of time ATI was in the "catching-up" position in relation to NVIDIA. There were certain reasons for that: take, for instance, the RADEON chip announced about a year ago. This chip being a response to NVIDIA GeForce2, was really late to come. It had about the same performance as GeForce2 did, but was considerably more expensive. ATI turned out very stubborn and didn't want to cut down the prices until the end of year 2000, and that's why RADEON still didn't reach the popularity of GeForce2. After all, the customers voting with their wallets for a more expensive graphics card wanted to see its indisputable advantages. But it was obvious that RADEON unfortunately had not so many advantages comparing to GeForce2, especially to approve of a high price like that. The other factor that led to the drop-down of RADEON popularity was the quality of the drivers. The RADEON drivers caused so many complaints that they were just scaring away the customers against the background of the constantly improving NVIDIA's software developers. Now we see the outcome of that: NVIDIA is the absolute leader in the gaming graphics card market.

But ATI seems to have learned its lesson, and the release of RADEON 8500 appeared a very painful blow to NVIDIA.

First, RADEON 8500 proved to be faster and more perfect than GeForce3. Second, ATI RADEON 8500 graphics cards turned out to be cheaper than GeForce3 Ti500, which can be regarded as none other but a preventive move against NVIDIA's pricing policy. Third, ATI released normally working drivers for RADEON 8500.

So, let us have a look at the solution that let ATI hope for winning the leadership.

ATI RADEON 8500 Chip: Closer Look

Here follow the basic characteristics of ATI RADEON 8500:

General specifications:

• 0.15micron manufacturing technology;
• 60 million transistors;
• 250MHz - 300MHz core frequency;
• 128bit graphics memory bus;
• Supports SDRAM/SGRAM, DDR SDRAM/SGRAM;
• 16MB - 256MB supported graphics memory capacity;
• Up to 300MHz graphics memory frequency, synchronous with the core;
• Supports AGP 2x (3.3V), 4X (1.5V), SBA, DMA, DiME;
• Supports power control with ACPI 1.0b, OnNow and IAPC.

3D Graphics:

• 4 pixel pipelines with 2 texturing units each;
• Single-pass texturing with up to 6 textures, 2 textures per clock;
• Tri-linear and anisotropic filtering;
• Bump mapping support: Emboss, EMBM and Dot3 methods;
• SMOOTHVISION 2x-6x full-scene anti-aliasing;
• DirectX 8.1 pixel shaders up to version 1.4;
• DirectX 8.1 vertex shaders up to version 1.1;
• Hardware fixed-function T&L unit;
• TRUFORM technology;
• Hidden surfaces removal (HSR) algorithm - HYPER Z II.

2D Graphics:

• Two integrated CRT-controllers;
• Integrated 400MHz RAMDAC;
• Embedded TMDS-transceiver for digital monitors;
• Multi-monitor configurations and HYDRAVISION support;
• Hardware MPEG2 decoding (iDCT);
• Supports Video-In / Video-Out in case of ATI Rage Theater chip;
• Supports GDI functions including Windows XP GDI extensions.

All the specifications make RADEON 8500 look if not more impressive, then at least as strong as NVIDIA GeForce3 Ti500, the today's gaming 3D-graphics king.

The first thing that catches our eye is the fact that ATI developers gave up the idea of using three texturing units in the pipeline. Apparently, the sad experience of RADEON 256, which third texturing unit stayed idle most of the time, inspired ATI to make the same decision as GeForce3 developers did. RADEON 8500 is capable of texturing polygons with up to 6 textures at a time, spending one extra clock cycle in case of more than two textures and one more extra clock cycle in case of more than 4 textures. GeForce3 chips from NVIDIA (now already GeForce3 Ti 200/500) lay up to 4 textures in absolutely the same way, having only 2 texture units per each pixel pipeline.

The second interesting feature of RADEON 8500 is the fully fledged support for multi-monitor configurations. It is the first gaming chip that boasts not only high 3D performance but also provides fully fledged support of multi-monitor configurations.

Thus, RADEON 8500 supports new technologies side by side with the old ones, which stood the test of time and have been certainly improved since the times of RADEON 256. That's why it is better to start with the technologies implemented in RADEON 8500 and their peculiarities.

New Technologies: TRUFORM, SMARTSHADER, SMOOTHVISION and HYPER Z II

ATI is showing the graphics pipeline of RADEON 8500 on the following flowchart:

Looking at this flowchart, we arrive to an interesting conclusion: the triangles tessellation (splitting) is performed before processing in the T&L unit and vertex shaders are applied to the already "chopped" triangles. This implies that the TRUFORM technology support is not painless and could lead to a significant performance loss in case of heavy tessellation, because the great number of triangles obtained as a result of TRUFORM technology could lead to a significant load increase for T&L unit and vertex shaders.

A few words about the TRUFORM. This technology is implemented in RADEON 8500 on the hardware level. It allows improving the models quality in games by tessellating triangles that make up those models. This tessellation uses information about the directions of normals at the triangle vertices. RADEON 8500 uses this information to build an N-Patch, i.e., a surface which curvature is defined with control points, and to split it into smaller triangles. Their quantity is determined by the level of tessellation:

The tessellation principles used by TRUFORM technology are described in great detail in the official white paper on the ATI website, so we will not repeat anything, but will just illustrate the TRUFORM algorithms discussed in that document:

  

As a result of TRUFORM technology application, the model appears smoother and more natural, and the most important thing is that the accelerator doesn't need any extra data. The normals, which are mostly passed over to the accelerator, already carry enough info for it to calculate the lighting, for example.

Therefore, the TRUFORM technology is expected to improve models quality in existing games without involving extra programming efforts (there are patches for some games enabling TRUFORM).

But in practice far not everything goes that easy. If all the models got smoothed, then those objects that need some edgy elements in their shape, for example, some weapons, would become a sorry sight: imagine a gun or a rifle with muzzle shaped like a cucumber… So, the software guys should still be involved in the process in order to avoid disappointments: for some polygons tessellation should be disabled, for other polygons -enabled, some objects may need an extra polygon added, the other may need one removed, and so on. At the moment, using TRUFORM in existing games brings about a less impressive result than one could imagine.

Our resume is that TRUFORM is certainly a smart technology, but its capabilities and peculiarities have to be undoubtedly taken into consideration when the games are developed, otherwise it will not show its best and will not prove a real advantage of the graphics cards supporting it.

And now that the due application for TRUFORM has not been found yet, we can only wait for some new games and hope to see a proper implementation of this cool technology one day.

The name SMARTSHADER covers both: pixel and vertex shaders of RADEON 8500, which were called PIXEL TAPESTRY II and CHARISMA ENGINE II.

The vertex shaders unit of RADEON 8500, as well as that of GeForce3, is capable of processing shaders up to 128 commands long and has 96 constant and 12 temporary registers:

The pixel shaders unit of RADEON 8500 is more advanced compared with that of GeForce3: it can process shaders up to 22 instructions long, which are transformed into the settings of the pixel shader unit: 6 texture sampling operations, 8 addressing commands and 8 shading commands:

Just for a better comparison: the pixel shaders unit of GeForce3 is capable of working with a maximum of 4 textures, and the pixel shader length may be up to 12 commands - 4 sampling operations and 8 shading operations.

In addition to all this stuff, the pixel shaders unit of RADEON 8500 supports unified addressing and shading commands, which correspond to the DirectX 8.1 pixel shader specification v1.4.

The clear and simple conclusion is that RADEON 8500 does not only support pixel and vertex shaders of DirectX8.0 and DirectX8.1, but can also show more progressive "special effects" because of its richer possibilities than those of GeForce3, or cope with difficult effects faster than GeForce3.

At present the pixel shaders v1.4 are used only in ATI demos, and again we've got to be patient and to wait for the implementation of these features in future games.

SMOOTHVISION is a new full-scene anti-aliasing method, acting like DirectX 8.0 Multi-Sample Buffer, which in its turn comes from the idea suggested by the late 3dfx in its T-Buffer technology some time ago.

The full-scene anti-aliasing of RADEON 8500 is implemented the same way as in Voodoo5. It is based on small shifts of scene geometry (Vertex Jittering) and further combining of colors of the obtained "shifted" samples. However, this idea is implemented in RADEON 8500 more successfully. First, ATI claims that RADEON 8500 may use up to 8 samples to produce the pixel color (Voodoo5 can use up to 4 samples). And second, RADEON 8500 may choose an optimal number of samples for further processing depending on the pixel location (a pixel may be situated at the edge of a polygon or inside it). This way it appears possible to prevent certain areas from being smoothed.

Let us make a preliminary conclusion: the implementation of full-scene anti-aliasing in RADEON 8500 is totally different from that in GeForce3, and should definitely surpass in quality the FSAA in NVIDIA GeForce3.

The current ATI drivers allow forcing SMOOTHVISION in OpenGL as well as in Direct3D, but the maximum number of samples is currently limited by 6 probably due to some performance issues.

We naturally couldn't help paying attention to the differences in image quality and performance losses caused by turning on the SMOOTHVISION technology. The results and conclusions will follow.

HyperZ II is an improved version of HyperZ technology, which advantages and algorithms we have already discussed in great detail in our ATI RADEON LE Review.

HyperZ and HyperZ II serve to increase the performance of the graphics accelerator by implementing the Hidden Surface Removal (HSR). That means that it should save the core time and trouble drawing those parts of the scene objects that are hidden behind closer located objects, as drawing them makes absolutely no sense and is just a waste of time and effort.

For example, imagine a scene in a game, which consists of two rooms separated by a closed door, and your character is standing in one of the rooms facing the door. Then, if you have a badly optimized game engine, it would accurately send all the polygons of the scene to the accelerator to be drawn, though the second room is completely hidden by the closed door, and drawing its interior would be a waste of time for the accelerator. The task of HSR is whenever possible to prevent the accelerator from useless activity like that. And the higher is the Overdraw, the greater performance gain can be granted by the HSR.

ATI developers have been improving HyperZ of RADEON 256 for over a year since it emerged. They reduced 4 times the tile of Z-buffer and introduced a number of other changes, the most important of which is the enhancement of Z-buffer compression algorithm. All those changes are promised to lead to an average 20-percent increase in accelerator performance.

Well, enough for the theory, let's carry on with some practice. :-)

ATI RADEON 8500 Graphics Card: Closer Look

The retail version of RADEON 8500 is shipped in a huge, aggressively designed box:

The package includes a CD disk with the drivers, a user's manual and a set of cables for all possible purposes:

The graphics card is equipped with an analog Out for a monitor and also both DVI- and TV-Outs. The card's PCB doesn't strike as vividly colored: it is made of traditional green textolite:

  

The heart of this graphics card is the RADEON 8500 chip working at 275MHz clock frequency.

There are 64MB of memory installed (128bit DDR SDRAM), the chips are made by Hynix (former Hyundai) and feature 3.6ns access time.

The graphics memory clock frequency is 550MHz (275MHz DDR). It's remarkable that the graphics memory of RADEON 8500 works well at higher frequencies compared to the memory of GeForce3 Ti 500. Moreover, the memory chips require no heatsinks for heat dissipation (and noise shielding). And even the cooler on a chip doesn't boast any impressive look as by GeForce3 or GeForce3 Ti500 based solutions. This shows that the RADEON 8500 card layout is of better quality and the core heat dissipation is smaller than by GeForce3 Ti500.

The TV-Out is implemented via ATI Rage Theater chip:

The card also incorporates an external ADV7123 RAMDAC from Analog devices, which sends the analog signals to the DVI-connector along with digital signal coming from an integrated TMDS-transceiver. The DVI-to-VGA adapter in the package allows to connect two analog monitors to the board. But the image quality for the second monitor won't be that high because the external RAMDAC supports only 240MHz.

Drivers and Utilities

The CD disk, which comes with the board, contains drivers for Windows 9x, 2000, NT and XP alongside with DVD and VideoCD software players, and DirectX 8.0. The drivers provided on the CD disk do not support SMOOTHVISION that's why for our tests we used the newer driver version with SMOOTHVISION support.

The graphics card properties in "Display Settings" look mostly like in case of older drivers:

However, as you may notice, OpenGL and Direct3D properties pages now provide links to SMOOTHVISION. If you click these links, you will get into SMOOTHVISION properties page:

Since RADEON 8500 fully supports multi-monitor configurations, it has a special properties page for multi-monitor configurations. You can find more details on RADEON 8500 working in multi-monitor configurations, with DVI and TV-Out in our ATI RADEON VE Review, as RAVEON VE and RADEON 8500 boast similar features here.

Testbed and Methods

Our testbed was configured in the following way:

• AMD Athlon XP 1600+ CPU, 266MHz FSB;
• ASUS A7V133-C mainboard;
• 2 x 128MB PC133SDRAM NCP;
• IBM DTLA 307020 20GB HDD;
• NEC DV-5700B DVD-ROM.

For a better comparison we ran extra tests with Intel Pentium 4 1400MHz CPU, a mainboard based on Intel 850 chipset and 256MB RDRAM.

We decided to compare the performance of our today's hero with that shown by Leadtek WinFast based on NVIDIA GeForce3 Ti500 and Leadtek WinFast based on GeForce3 Ti200 working at standard frequencies. Later on we'll refer to them just as GeForce3 Ti500 and GeForce3 Ti200.

Taking into consideration that currently RADEON 8500 LE cards have appeared in the market (they differ from ATI RADEON 8500 by lower price and lower frequencies, working at 250MHz/250MHz vs. 275MHz/275MHz of the regular RADEON 8500), we decided underclock our RADEON 8500 and to test it at the working frequencies of RADEON 8500 LE, i.e. at 250MHz/250MHz.

We used the following software:

• Windows 98 SE build 4.10.2222A;
• DirectX 8.1;
• Driver version 4.13.7206 for ATI RADEON 8500;
• Driver version 21.85 for NVIDIA GeForce3 Ti500/200.