ATI Radeon X1900 XTX review -
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To give you an more understandable example: the X1800 could manage 60 million Pixel shader operations per second. The X1900 can do 166 million. With the extensive Shader Model 2 and 3 that alone is the money shot right there and yeah let's not forget that Shader Model 3.0 finally became very important.
What is a shader ? |
What do we need to render a three dimensional object; 2D on your monitor? We start off by building some sort of structure that has a surface, that surface is being built from triangles and why triangles? They are quick to calculate. How's each triangle being processed? Each triangle has to be transformed according to its relative position and orientation to the viewer. Each of the three vertices the triangle is made up of is transformed to its proper view space position. The next step is to light the triangle by taking the transformed vertices and applying a lighting calculation for every light defined in the scene. At last the triangle needs to be projected to the screen in order to rasterize it. During rasterization the triangle will be shaded and textured.
Graphic processors like the GeForce and Radeon series are able to perform a certain amount of these tasks. The first generation was able to draw shaded and textured triangles in hardware. The CPU still had the burden to feed the graphics processor with transformed and lit vertices, triangle gradients for shading and texturing, etc. Integrating the triangle setup into the chip logic was the next step and finally even transformation and lighting (TnL) was possible in hardware, reducing the CPU load considerably. The big disadvantage was that a game programmer had no direct (i.e. program driven) control over transformation, lighting and pixel rendering because all the calculation models were fixed on the chip. And now we finally get to the stage where we can explain Shaders. Vertex and Pixel shaders allow developers to code customized transformation and lighting calculations as well as pixel coloring functionality. Each shader is basically nothing more than a relatively small program executed on the graphics processor to control either vertex or pixel processing. |
SM3 allows the programmer to fire off some very nice shader programs that in certain cases can speed up your game. The world has moved on to SM3, people expect it to be integrated and so it has and had to be been done. Very good integration I might add because SM3 seems to work pretty darn efficiently for ATI, it has to do with dynamic branching, that matter is too complicated to explain for this article. What you need to know is that it works really well. More efficiency, that really is what the new card is all about. I'll be using that word in this review a lot. According to the chip designers every transistor in that core is constantly put to use to push the results onto your screen, yes efficiency.
Another feature in the X1000 and now X1900, and yeah it's not new to our ears at all, yet it had a little upgrade has to do with texture compression capabilities. Almost any, well any, graphics card nowadays makes use of texture compression technology. It's been discussed here on more then one occasion, I'm sure you recognize terms like S3TC and DXTC. Basically you reduce the byte-size of a texture while maintaining the best quality as possible. However, compression equals artifacts and thus image degradation at some point. 3Dc is a compression technology designed to bring out fine details in games while minimizing memory usage. It's the first compression technique optimized to work with normal maps, which allow fine per-pixel control over how light reflects from a textured surface. With up to 4:1 compression possible, this means game designers can now include up to 4x the detail without changing the amount of graphics memory required and without impacting performance.
3Dc was upgraded a little and on the X1000 series of cards we now have 3Dc+ available to us. Let me just get it out of the way and move on. High quality normal map compression can (and could) be handled up to a 4:1 ratio and works on any two-channel texture format.
This updated + edition adds support for single-channel textures with 2:1 compression, which is good enough for stuff like luminance maps, shadow maps, HDR textures and more.
What about the cards then?
Let me present you the entire X1900 range of cards as they will be available today. My bet is that you'll see a lot of reviews as of today.
- Radeon X1900 All-in-Wonder 500 MHz core / 500 MHz (x2) memory, 499 USD
- Radeon X1900 XT 625 MHz core / 725 MHz (x2) memory, 549 USD
- Radeon X1900 Crossfire (master card) 625 MHz core / 725 MHz (x2) memory, 599 USD
- X1900 XTX 650 MHz core / 775 MHz (x2) memory, 649 USD
Guru3D fact: One MHz represents one million cycles per second. The speed of microprocessors, called the clock speed, is measured in megahertz. For example, a graphics processor that runs at 600 MHz executes 600 million cycles per second. Each computer instruction requires a fixed number of cycles, so the clock speed determines how many instructions per second that processor can execute.
Planning Crossfire? You need to know this.
The observing ones among you immediately notice that there will be no XTX Crossfire card, this is correct. If you want to go Crossfire on the 1900 then that XT is the only solution you'll have. Mixing XTX and the Crossfire XT would not make sense as the XTX would drop down in speed to balance the XT performance. So if you want to go for Crossfire now or in the future then just stick with the X1900 XT.
The prices of course are manufacturer suggested retail prices and might even be cheaper in e-tail.
Radeon card
Pixel Shader Units
Vertex Shader
UnitsTexture Units
Max Threads
Core Frequency
Memory Frequency
Memory
Price in USD
Available
X1900 XTX 48 8 16 512 650 775 512 gDDR3 649 Now X1900 Crossfire 48 8 16 512 625 725 512 gDDR3 599 Now X1900 XT 48 8 16 512 625 725 512 gDDR3 549 Now X1900 AIW 48 8 16 512 500 500 256 gDDR3 499 Now X1800 XT
16
8
16
512
625
1.5 GHz
256/512 gDDR3
499 / 549
Now
X1800 XL
16
8
16
512
500
1.0 GHz
256 MB gDDR3
449
Now
X1600 XT
12
5
4
128
590
1.38 GHz
128 / 256 MB
199 / 249
Now
X1600 PRO
12
5
4
128
500
780 MHz
128 / 256 MB
149 / 199
Now
X1300 PRO
4
2
4
128
600
800 MHz
256 MB
149
Now
X1300
4
2
4
128
450
500 MHz
128 / 256 MB
99 / 129
Now
X1300 Hypermemory
4
2
4
128
450
1 GHz
32 / 128 MB
79
Now
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