SLI and CrossFire: There's a Sucker Born Every Minute

Poor Maury. You can sense the inner turmoil in his words. On the one hand, he's got a solid technical understanding of computer graphics, and the real-world factors that mold the importance of various graphics chip and board features. He predates me as EDN's computer peripheral editor, after all; he's been living and breathing this stuff even longer than I have, and although the nuances have evolved, most of the fundamentals haven't changed.

On the other hand there's his son, who's been seduced by the sly marketing folks at ATI and Nvidia, along with their graphics and system board partners, in cahoots with the computer game magazine ink-slingers. Maury's son is convinced that he needs the latest-and-greatest, most expensive GPU (graphics processor). Two of them, actually, in a dual-board configuration. And it's not even Christmas.

Even though Maury already knows, and I've reminded him, that his son's eyeballs and brain likely aren't going to be able to discern the quality difference that advanced anti-aliasing modes supposedly deliver. Specifically on the fast-twitch first-person-shooter games that his son likes to play. And especially at XGA resolutions, and on anything smaller than a wall-sized projection screen. And that even if his son's visual system valued high-end anti-aliasing enough to pay extra for the privilege, it wouldn't be able to discern frame rates any faster than around 30 fps…the triple-digit frame rates touted by latest-generation GPUs at high-quality settings just aren't necessary.

Nvidia's SLI (Scaleable Link Interface, a rebirth and extrapoliation of the Scan Line Interleave technology that they acquired when they bought the technology assets of 3dfx), along with the CrossFire dual-board alternative that rampant rumour suggests ATI will soon launch in product form (the technology concept is already public), remind me a lot of the OverDrive program that my CPU counterparts down the hall at Intel used to tout. Like any successful marketing program, they all convince you to spend more money that you otherwise would….both now, and in the future. First, a review of OverDrive. By the 486DX CPU generation, Intel had integrated on-CPU the math coprocessor (predominantly also sold by Intel) that previously resided in a separate socket next to the microprocessor. But then Intel started internally multiplying the clock that was externally supplied to the CPUs, leading to the DX2 and DX4 generations.

So Intel convinced its motherboard partners to cost-burden their designs with a separate OverDrive socket, intended to house a slightly pinout-altered variant of the DX2 or DX4 CPU. Here's the pitch: buy a 486DX CPU-based system now and a few months or years down the road, instead of buying a completely new system, just drop in a DX2 or DX4 OverDrive processor that'll disable the original CPU and turbo-charge the PC. The mantra sounded good. It actually reflected reality, or at least some semblance of it. And waves of consumers drank the Kool-Aid and paid extra for OverDrive-capable systems (that, not coincidentally, also weren't AMD-based systems). But very few of them actually ever dropped in an OverDrive CPU (I know this for a fact….I've seen the stats). Why?

Even though the CPU got upgraded, the rest of the system did not. So from a performance standpoint it still contained prior-generation DRAM, prior-generation HDDs, prior-generation graphics, and the like. Plus, it didn't deliver all the whiz-bang new architecture features that were appearing, such as AGP and USB. When push came to shove, most folks just shelled out the extra bucks and bought a new system anyway.

Continued with 'Suckers: the Second Half of the Story'….