Graphics cards for beginners

If you're confused by the wealth of choice when it comes to graphics cards, then fear not. We've looked at the common issues, and our guide should help you decide which card is right for you.

OpenGL

If you're not on Windows, odds are that programmers are accessing 3D hardware through an API called OpenGL.

This standard graphics API is controlled by a collaborative entity called the Khronos Group, which has members from lots of big software and hardware makers. OpenGL is available and used on Windows (in fact, the newest version of Photoshop uses it for GPU acceleration), but it isn't as common as Direct3D.

These days, all modern GPUs (discrete and integrated) provide both OpenGL and DirectX drivers.

OpenCL

Remember when I mentioned that GPUs can be used for general computing (like video format conversions, heavy scientific calculations, and such)? Well, OpenCL is a standardised way of doing this.

An OpenCL program can run on and be accelerated by the GPU, regardless of who the GPU manufacturer is. It's a brand new standard, appearing in both Apple's new Snow Leopard OS and Windows (XP, Vista, and 7).

Neither nVidia nor ATI have real, final, public OpenCL drivers yet. This is a technology that is in its infancy, but should grow rapidly. Robust OpenCL support and good performance will probably be a real selling point in the next year or two.

Drivers, drivers, drivers

No matter what graphics processor you have, you need the latest drivers. For nVidia cards, go here. For ATI cards, go here. For Intel integrated graphics, go here. If you have a laptop, you may need to go to your laptop manufacturer's website to get the latest drivers.

DirectX 11

Microsoft's marketing department is doing its best to brand DirectX 11 as a Windows 7 thing, but the truth is that it's coming to Vista as well. This new version of the API brings with it several new features. It's too much to go into here, but the short list is:

• Better use of multi-core CPUs
• Tessellation - This is the fancy word for breaking up an object made of a small number of triangles (and thus blocky-looking) into a very large number of triangles, which can then be manipulated to make the object look smoother or more detailed.
• DirectCompute - (aka 'Compute Shaders') - Like OpenCL, this is a standardised way to make and GPU with DirectX 11 drivers do general computational stuff.

Laptop buying advice

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NEXT PAGE: CUDA and ATI Stream

1. The issues you need to consider when purchasing
2. What happens when you're not on Windows
3. CUDA and ATI Stream
4. SLI and Crossfire