SiS Xabre 600 Impressions

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SiS Xabre 600: Impressions
The GPU That Scales With Your Processor

By: Chris Angelini
November 26, 2002

There isn't much room for error in the graphics market - just ask someone who worked at 3dfx.  The current landscape is fairly barren for gaming enthusiasts, save the recent success ATI is enjoying and NVIDIA's GeForce FX announcement, which will hopefully yield actual product sometime in February.  Conversely, there is a lot more action taking place in the mainstream, where volume is the name of the game.  NVIDIA has been busy revamping the GeForce4 MX 440 and Ti 4200 cards with AGP 8x support.  And, ATI is putting the finishing touches on its RADEON 9500 and 9500 Pro products to compliment the already-compelling RADEON 9000 Pro. 

Not one to be left out in the cold, SiS has been hard at work, improving upon its Xabre 400, which it debuted earlier this year.  Make no mistake - the retooled Xabre 600 won't contend in the same ring RADEON 9700 Pro or GeForce FX.  Rather, SiS is planning a full frontal assault on the mainstream market.  The Xabre 400 was plagued with driver issues, though, so it will certainly be interesting to see how SiS has addressed its prior faux pas. 

Xaber 600 Architectural Block Diagram
High level of integration

 

Of course, no product launch would be complete without the introduction of a few new marketing terms.  This one is no exception; some carry over from the Xabre 400 launch and a few are new. 

Vertexilizer Engine

The first new term reflects the Xabre 600's ability to distribute the vertex shading load between the GPU and CPU in order to achieve what SiS considers to be an optimal balance between dedicated graphics hardware and overall performance.  The benefit of this design is two-fold.  First, as CPUs become faster, the graphics processor scales accordingly.  Secondly, the vertex shading can be upgraded independently of the hardware, so theoretically, the shading engine could be upgraded to support the Vertex Shader 2.0 specification contained within DirectX 9. 

SiS' own demonstration of the Vertexilizer Engine scaling with processor performance.

Pixelizer Engine

Pixel shaders can't be emulated, so SiS does include a Pixel Shading engine on the Xabre chip itself, compatible with the DirectX 8.1 1.3 specification.  Coupled with the Vertexilizer engine, SiS is able to claim full DirectX 8.1 support.

Frictionless Memory Control

As graphics hardware becomes more powerful, addressing the need for memory bandwidth becomes ever-important for hardware manufacturers.  ATI implemented first included HyperZ on it's RADEON, and NVIDIA soon followed suit with the Lightspeed Memory Architecture.  Both implementations are designed to optimize available bandwidth using compression, fast Z-buffer clears and occlusion culling.  SiS also delivers a similar strategy, and is aided by a 128-bit memory bus on which resides 64MB of DDR memory operating at 300MHz.  Without the benefit of the FMC, the Xabre 600 enjoys a peak memory throughput of 9.6GB per second. 

Xmart Technology

SiS has wrapped its latest software developments into a package dubbed Xmart.  The first component of Xmart, XmartDrive, provides for frequency throttling of the Xabre 600.  Though it may be an interesting feature for mobile users, desktop customers don't need to pay much attention.  Secondly, SiS has developed XmartAGP, similar in design to ATI's SmartGART, which automatically sets AGP speeds to match the capability of your motherboard (again, not something that requires much attention).  XmartVision is also included to adjust brightness in 3D environments that may be a little too dark.

Most significant is the Xminator II driver package, which addresses many of the issues originally encountered with the Xabre 400.  SiS has added a texture slider in both the OpenGL and DirectX property pages, as well as an overclocking utility.  It should be noted that using the Xabre 600's default texture setting, 3D quality suffers heavily.  Maybe we've been playing too many games, maybe we've tested too many video cards, but the discrepancy between the GF4/RADEON 9000 is significant enough to be a distraction.  Thus, our benchmarks reflect performance with both DirectX and OpenGL sliders set to "Quality."  Just for the sake of comparison, though, here is how the Xabre 600 performs at each setting:

Clearly, the texture slider has a significant impact on performance (and quality as well), so if quality doesn't bear the same weight as performance, consider this graph representative of performance in 3D Mark. 

The Card, Overclocking and System Setup 

 

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