If you have a Pentium 166 or better and are happy with your existing primary (2D) graphics card, the easiest thing to do is to upgrade to Voodoo2. Now, Voodoo2 won't buy you a lot of performance difference over Voodoo Graphics in a Pentium 166, but with the prices of Voodoo2 boards are dropping faster than the Moscow stock market - and you'll have a decent accelerator to carry over to your next system.
If your system is saddled with a poor 2D card, you might consider replacing it with a 2D/3D card. A lot depends on your budget here. If you have a tight budget, a board using the 3dfx Voodoo3 chipset might be the answer. The new Voodoo3/2000 is available in PCI format as well as AGP. It doesn't render in 32-bit color or support 32-bit z-buffer, but your CPU horsepower probably wouldn't support that anyway.
If you have a bigger budget, you have a couple of choices: buy a fast 2D/3D card and a Voodoo2 card or buy a Voodoo3 board and save up for your next system upgrade. If you plan to move to an AGP system in the next six to nine months, then buying a high-performance PCI 2D/3D accelerator may just be wasted cash. A Voodoo3/2000 board goes for close to $100 (even less than $100, in some cases), and it's a good deal.
Pentium Pro Systems
Much of what I wrote about Pentium systems in the previous section applies to Pentium Pros. However, most Pentium Pro systems shipped with relatively decent 2D cards, so adding Voodoo2 may be the right thing here. The faster floating-point unit of the Pentium Pro is capable of feeding the 3dfx card polygons at a faster rate than a Pentium-based system.
