ATI Radeon X1900 XTX review - Page 3

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.