Dual Wielding Video Cards
Before you run out and buy that second card though, there's a lot you need to check on first to make sure two video cards are even an option.
Is Your Computer Compatible?
First off, you need to find out if your motherboard can support two video cards. If you don't know already, find the model name and look it up online. Most high-end computers from the last 2-3 years, like the iBUYPOWER Paladin XLC Series gaming system, support it, but you won't know until you do the research. The reason for this is that SLI-capable motherboards are typically not compatible with Crossfire-capable motherboards (except for newer Intel P55 or X58 chipset motherboards, most of which are compatible with both).
Next, you need to make sure that the new card you plan on getting is compatible with your current video card. Most new discrete graphics cards from ATI (CrossfireX) and NVIDIA (SLI) are capable. CrossfireX may be installed with two different cards of the same family, but the benefits of this are fairly limited so it's not a good way to spend your money.
You'll also need a power supply that can support the additional card. A good margin to have is 20% above the power requirements of your CPU, video card and drivers combined. CPUs are generally 80-140 watts, video cards can consume up to 150-250w each, though lower-end cards may use a lot less, and optical and hard drives are typically 50-100w total for all drives. If you don't have at least a 20% overhead, you'll wear out your other components. Plus, running at peak output will draw more power from the outlet, which will increase your power bill.
If you do need a power boost, you have two options. The first is to buy a video card power supply, but these are sometimes hard to find. The other option is to get a whole new power supply, but be sure to buy one from a reputable manufacturer (Corsair and Thermaltake are good options).
Finally, your case needs to have sufficient cooling as well. You can monitor the temperature of your cards in the video card drivers menu (ATI cards only), or you can download a third-party monitoring software. 75-85°C is generally acceptable for video cards, but different cards heat up differently. If your games crash to the desktop with the error, "Your video card drivers have stopped responding and have been restarted," then you're overheating your video cards.
Once you've made sure everything is compatible, cooled and has enough power to back it up, it's time to install your new card. Installation is a simple matter of plugging the card into an available slot, connecting the proper power connectors and then connecting the two cards with a CrossfireX/SLI "bridge" cable. Once everything works, there will then be an option to "Enable CrossfireX/SLI" in the graphics card drivers menu.
The last step may be the simplest, but that's because figuring out if all of the pieces fit is the hardest (and most important!).
For more info on IBuyPower go to www.iBuyPower.com or call Toll Free- 1-888-462-3899. They have laptops and Home Computers that we highly recommend!