It wasn't long ago that the smart money bet against -- and PC performance buffs sneered at -- any component that was integrated onto a desktop motherboard instead of an expansion card. Savvy users viewed integrated platforms as inferior to dedicated hardware, and not without reason: Years ago, the integrated motherboards of many entry-level or economy PCs were practically dumping grounds for past-their-prime, bargain-basement parts.

Lately, however, this scenario has changed -- often dramatically. While cost-no-object hot-rodders can still get supreme performance from separate components, the days of motherboard mystery parts and drivers have come to an end. As hardware evolution hits its apex, onboard audio chips, network adapters, and hard-disk controllers can capably provide all the features a general user might want.

Today, we're even seeing respectable motherboard-based alternatives to the last bastion of dedicated hardware -- graphics cards. To be sure, no integrated graphics controller is going to challenge the likes of ATI's Radeon 9700 Pro for the benchmark speed crown or the hearts of avid gamers. But mainstream PC users are finding that integrated video's speed, support, features, and quality continue to improve.

Designing a powerful yet affordable integrated graphics component is one of the hardest challenges in PC architecture. Yet, due to the historic gulf between integrated and dedicated graphics, it's also one of the areas where a company can make up the most ground -- and some heavy hitters today, ranging from Intel to Nvidia, are doing just that.

From Card To Motherboard To Chipset

Older integrated video solutions simply moved the graphics controller and display memory chips from an AGP or other expansion card onto the motherboard (as many notebook PCs do to this day). This is integrated video in name only, as there's still dedicated hardware at work; it's just mounted alongside the CPU, chipset, and system memory, instead of occupying a slot.

One of the most fundamental shifts in recent desktop design, however, has been to integrate the graphics hardware directly into the system chipset (typically the Northbridge component), while borrowing a portion of the main system memory for the display buffer. (See "Your PC's Second Most Important Silicon" for an introduction to chipsets and their functions -- Ed.)

Today, chipsets fall into three categories, illustrated here by Intel's block diagrams of its 845 family. First are designs without video functionality of their own, like the 845PE ...

Second are economy-model chipsets with integrated video only and no provision for an AGP-slot alternative, such as the 845GV ...

And third, as you've probably guessed, are chipsets that give the system builder or PC buyer a choice of either integrated or dedicated graphics, such as Intel's 845GE. Such chipsets, paired with motherboards with AGP slots, are the best choices for buyers looking to save money at purchase time but not seal off potential upgrade avenues for the future.

The most obvious benefit of integrated chipsets is lower system cost: No matter how inexpensive a separate video chip and display memory may be, they can't compete against products like the 845GE, which in 1,000-unit quantities costs PC builders just $3 more than the 845PE. And chipset vendors are quick to provide reference motherboard designs which result in easier implementations, especially compared to hard-wiring a dedicated video chip onto an existing motherboard.

Chipset integration has also provided most new integrated graphics cores with a direct AGP 4X or 8X pipeline to system memory (even if no physical AGP slot is present), while older, dedicated video-chip solutions were usually placed on the slower PCI bus, which meant having to take a longer route and contend with competing data requests.