What is SLI graphics?

Only the most tricked-out desktop PCs and laptops have multiple graphics cards (GPUs) configured in what’s called a scalable link interface (SLI). A graphics card is a secondary processor devoted expressly to rendering graphics; to have two of them, each with their own reserve of video memory, gives a computer that much more muscle to smoothly render the demanding graphics engines behind many of today’s most cutting-edge video games.

Both Nvidia and ATI, the two leading GPU manufacturers, have their own line of SLI-enabled cards; currently, laptops can accommodate a maximum of two GPUs, while desktop PCs can handle up to four, which is sometimes referred to as quad SLI.

Take note: only the most competitive, hard-core gamers should shell out the money required to configure a computer with SLI.

Justin Jaffe, the author of CNET Do-It-Yourself Laptop Projects: 24 Cool Things You Didn't Know You Could Do!, is a writer and technology expert in Portland, Maine.