I receive a lot of mail nowadays from people who don't know which graphic accelerator card to get and I can understand that there are a lot of choices for all kind of different needs. There's a lot of hype thrown at us from all the different card and chip manufacturers on the graphic market too and you can easily face a huge disappointment if you should make the wrong choice.
The difficulty in choosing the right video accelerator card comes from the different needs we have for this piece of hardware. As usual we'd prefer getting a card that can do everything at an excellent level and this if somehow possible for a low price as well. However the miracolous cheap all-round card isn't out yet and I guess that it will possibly take forever until all our needs will be pleased. Hence we have to make our mind up what is most important to us and also how much money we are willing to spend.
The first question we have to ask ourselves is if we will use our system mainly for professional work or mainly for games. Most professional cards are not great at games and vice versa. If you've already got a video card in your system, ask yourself if you're pleased with its 2D performance at professional work and if you just want to purchase an add on card for games. In this case you still have the professional performance of your current video card and add some real good gaming performance with the add on 3D card. You will need an additional PCI slot though.
Considerations For Gamers
In case gaming is most that you do on your system and you couldn't care less for Windows NT, true color and OpenGL, you want to go for a pure 3D gaming card or get an add on card.
Direct3D Or Proprietary 3D Engine?
You'll now have to decide what kind of games are important to you. Currently the graphically best games are often designed for a special graphic chip, or at least they look best with this one chip. The number one supported 3D graphic chip is nowadays the 3Dfx Voodoo, found on add on cards like the Orchid Righteous3D, Diamond's Monster3D and several others. It looks as if upcoming games will still support this particular chip and since the Voodoo 2 is already on the horizon, you can expect 3Dfx's 'Glide' engine staying supported by many games for a long time. Alternatively to a special 3D chip support, many new games are using Direct3D's new features quite heaviliy, so that it depends on how well the 3D card's driver translates Direct3D to their proprietary engine. PowerVR's PCX1 and PCX2 chips are quite powerful 3D chips, but the cards that use them are highly incompatible. I've seen only very few games that run on this chip properly. If the PCX engine is used directly, the games look awesome though. The only 3D chip to my knowledge, that doesn't have a dedicated 3D engine, but is using Direct3D as its API directly, is NVidia's RIVA 128 chip, currently the fastest Direct3D chip available on the market. The RIVA 128 is wonderful for Direct3D games, but games that are only supporting a bunch of proprietary 3D engines will not run on the RIVA 128. The future will bring almost any game in Direct3D, which will help NVidia's RIVA a lot.
It is not easy to measure pure 3D performance, because there are so many different ways a 3D engine can be used. Most official benchmarks are using the Direct3D engine of DirectX, like e.g. ZD's 3D Winbench or VNU's Final Reality. These benchmarks can only show you the card's Direct3D performance, hence how well the driver translates Direct3D into the chip's own 3D engine. NVidia's RIVA 128 doesn't need this 'translator', it uses Direct3D as its own API. This is only one reason why the RIVA scores by far best in Direct3D benchmarks. However some games written for that specific 3D engine of a chip can run much faster than the 3D Winbench score would let you expect them to. VQuake for Rendition's Verite 1000 is one good old example. The Verite 1000 was never scoring well in 3D Winbench, but VQuake looked good and ran fast.
3D Quality !
Now 3D performance is only one thing, 3D quality is another. There are a lot of 3D features used nowadays, most of them supported and used by DirectX 5, but there will be even more 3D features implemented in DirectX 6. A 3D chip can only support a special amount of 3D features, others are either not supported at all, or special drivers are used that emulate these features. In my latest test I came across only one chip that supports virtually every current 3D feature properly and this is 3Dfx's Voodoo chip. The big let down of the Voodoo chip leads to the other aspect for quality, the 3D screen resolution. The Voodoo chip can only do 640x480 in case of 2 MB frame buffer memory (4 MB cards), as in most of the Voodoo cards, or maximal 800x600 in case the card comes with 6 MB RAM (e.g. Quantum 3D Obsidian 100SB ), 4 MB hereof as frame buffer. NVidia's RIVA 128 chip has got a simular problem, it can't support more than 4 MB onboard memory, only good for a 3D resolution of maximal 800x600. Now it doesn't have to be that bad, since we are quite pleased with our good old television as well, which has a lower resolution than 800x600. The 3D chip and the system CPU have to be powerful enough for running smoothly at this resolution as well. However, I've seen 'Forsaken' at 1024x768 on a PII 300 with an ATI XPERT card and it looks pretty awesome.
How Powerful Is Your CPU?
Some 3D chips are taking a lot of workload from the CPU, others want decent CPU performance for its operation. PowerVR's PCX chips want at least a Pentium MMX 166 for decent quality, 3Dfx's Voodoo lets games run fast even on systems with weak CPUs and Rendition's new Verite 2100/2200 chip gives a huge improvement to slow CPUs, but fast CPUs are reaching its limit and don't really benefit of this chip anymore. NVidia's RIVA chip seems to scale linearily from 6x86 CPUs up to Pentium II CPUs. Under Direct3D its always the fastest chip.
Another thing you obviously want to take in consideration is the price you've got to pay for the card. Many cards that have good 2D performance as well are pretty expensive. This is often due to the more expensive memory they are using, but it could also be the additional features like e.g. TV out or video compression. Cards with more memory are also more expensive, but they offer higher resolutions in 3D, higher color depth and higher resolutions in 2D. Make sure you don't pay for something you won't need.
Considerations For Professionals - Picture Quality
If you are working on your computer professionally one of the most important things is the picture quality. This is achieved by a high quality and high clocked RAMDAC. Most of the new graphic chips have included the RAMDAC internally, thus saving cost, but the best picture quality is still produced by an external RAMDAC. The most popular cards with external RAMDACs are Matrox Millennium I and II and Number Nine's Revolution 3D. These cards are still offering you the sharpest and cleanest picture on the screen. If you have got an expensive monitor, you want to use the high refresh rates your monitor supports. As a simple rule you should at least have a refresh rate of 85 Hz available for all the reolutions you want to use. Refresh rates of 120 and more sound nice, but they won't give you much of an advantage anymore. Responsible for this is again the RAMDAC. The higher its clock rate, the higher are possible refresh rates.
The 2D performance was what used to determine the quality of a graphic card in the past. Now 2D acceleration seems pretty close to the limit and almost all cards are offering a good 2D performance, at least at 16 bit color modi. Good 2D performance in true color is a virtue that's pretty rare still though. Matrox and Number Nine always used to fight about the 2D performance crown and it hasn't changed much still. If you are working really professionally at your computer, you can impossibly use Microsoft's mouse driver collection called Windows 95. Hence you are either using Windows NT or some really good OS that's not from the monopolist. NT drivers are very important for professional cards and the NT performance should be more important than the Windows 95 performance. There is often quite a bit of a difference between NT and 95 performance.
For people that use a real graphic workstation with CAD and/or 3D rendering, SGI's OpenGL as well as Heidi are of major importance. Nowadays if you hear 'PC' and 'OpenGL' one company comes into your minds ... 3DLabs. I will not discuss the real high end chips of 3DLabs, since this is off topic on this website, but 3DLabs' new Permedia 2 chip is one of the most impressive graphic chips on the market today in my opinion. For 3DLabs the Permedia 2 is nothing but a low end chip for the mass market, but amongst its competitors it's quite a gem in terms of professional work. In mid to higher prized systems cards with the Permedia 2 will offer you the best OpenGL performance combined with a good 2D and a fairly impressive Direct3D performance.
AGP Or PCI
Since the new advanced graphics port (AGP) has been released, you may wonder what interface to go for. I think you should certainly get a board with Intel's new LX chipset, in case you want to use a Pentium II system. In this case you won't do much wrong going for an AGP card. However please be aware that there's currently hardly any performance advantage of AGP over PCI. In case of Socket 7 there's still the problem that there aren't many AGP motherboards available yet, but this will hopefully change soon, now that the PA-2012 was released.