RAM | Reseller Advocate Magazine: Issue 75

By Chris Angelini

The practice of using multiple graphics cards for cooperative rendering is not new. The technology was first introduced by 3dfx in 1998 and made available to the desktop enthusiast market as SLI (Scan-Line Interleave) in its Voodoo2 3D accelerators. Today, a full decade later, SLI branding lives on through NVIDIA and its Scalable Link Interface. AMD’s competing solution is called CrossFire. Both value-added platforms are far more flexible than 3dfx’s best efforts, which required a separate 2D graphics board and a pass-through cable.

AMD’s CrossFire technology and NVIDIA’s SLI have each been around for several years, dancing the dual-adapter tango through many generations of GPU architectures. NVIDIA’s implementation took an early lead thanks to the internal bridges that connected a pair of SLI-compatible cards. Internalizing the SLI circuitry proved beneficial to system builders who could configure their machines and close them up with the technology ready to go.
The answer from AMD, championed back then by ATI, was a gangly external solution linking a pair of CrossFire cards with a pass-through cable. As a result, customers had to look for special CrossFire Edition boards with the requisite high-density connector to turn the technology on. In the channel, that meant inventorying an extra card for CrossFire-curious enthusiasts. It also meant shipping whiteboxes with the pass-through cable pre-configured or, more likely, with instructions for setting it up.
CrossFire and SLI have undergone a number of significant improvements, including an extension to more mainstream graphics cards. Now your customers can buy one budget-oriented board and add another down the road to help improve performance. Alternatively, multiple cards plugged into enthusiast motherboards can be used to scale display connectivity. Given that dual-link DVI connections are common fare now, a board with four PCI Express x16 slots will support as many as eight high-res digital displays.

AMD STEPS UP ITS GAME
With the introduction of its Radeon X1950 Pro, ATI reworked the way two CrossFire-compatible cards communicated with each other by eliminating the external dongle and special primary/secondary boards that had to be matched up. The technology adopted internal ribbon cables similar in function to NVIDIA’s SLI connectors.

VARs familiar with the Radeon HD 2900 series boards, released last year, may have noticed two CrossFire connectors on the top of AMD’s flagship boards. At the time, CrossFire only provided for two cards to render cooperatively. But the dual connectors were a harbinger of capabilities to come. AMD’s full story emerged with the introduction of its Spider platform late in 2007. Although AMD is new to the platform scene, previously sticking to its core competency as a processor manufacturer, it wanted its first foray to include multimonitor output, high-definition video, and gaming with all of the settings maxed out. In other words, AMD is reaching for the accolades bestowed upon the Athlon 64 before Intel introduced the Core microarchitecture. To that end, Spider includes support for CrossFireX, an updated implementation of CrossFire that incorporates new functionality sure to grab reseller attention—more so than any past iteration of the technology.

To begin, CrossFireX relies on the AMD 790FX chipset. Whereas the company once insisted that chipset development was best left in the hands of its partners, the 790FX demonstrates what Intel has known all along—owning your core logic pays. The chipset’s 38 lanes of PCI Express 2.0 connectivity are divvied up to favor graphics. In fact, 32 of the lanes are devoted to graphics connections, while six attach to peripherals.

Here’s where CrossFireX sets itself apart from the previous generation. By dividing those 32 lanes between four x16 slots electrically wired to run with eight lanes each, the quartet presents the same bandwidth available from a pair of PCI Express 1.1 links using all 16 lanes. It might sound ludicrous to nudge an enthusiast from two cards to four, but consider the growing popularity of multi-display configurations beyond two monitors. In the past you might have gone with NVIDIA’s Quadro NVS 440. But because that product hasn’t been updated for Vista, more powerful Radeons make great substitutes, scaling up to eight displays.

Moreover, enabling CrossFire acceleration on a previous-gen board would have turned off the signal to all outputs except the primary display. CrossFireX drives surrounding displays, even as a 3D app receives multi-card acceleration. Gone are the days when gaming technology conflicted with productivity apps.

PICK YOUR POISON
There are two different directions to go if you’re looking to enable CrossFire. One is with the aforementioned 790FX from AMD, and the other is Intel’s newest desktop chipset combo, the X38 and P35. The great news here is that resellers can build exciting platforms for the first time using either company’s core logic.

The Intel story should be a familiar one. There’s the Intel chipset sitting on an Intel motherboard with the company’s HD audio and Gigabit Ethernet controller built-in. You drop an Intel processor into the board’s socket, finishing up with memory from a trusted vendor and reliable storage. If you’re building on a budget, Intel’s integrated graphics solutions get the job done. When the buyer needs more 3D horsepower or output scalability, a board like Gigabyte’s GA-X38-DS4 delivers the goods with official CrossFireX certification.

Bear in mind that the X38’s PCI Express connectivity is divided between two x16 slots, limiting your customer to four monitors. Nevertheless, when you’re working on a workstation demanding Intel’s stability story along with a healthy dose of graphics performance, an X38 or P35- based board are your best bets“The drive itself incorporates encryption,” says Sparkes, “which has really helped growth. It has enabled us to eliminate some of the risk involved in shipping tapes around in trucks.”

If your personal information hasn’t been compromised at some point because a major corporation or government lost data (perhaps you received one of those “we’re sorry to report...” letters from a brokerage or credit card company sometime last year), then you’ve at least heard the stories on the news. “A company must divulge that it lost data on its customers publically,” says Quantum’s Sean Lamb. “That’s where encryption comes into play.”
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On the other hand, enthusiasts want to take their systems to the limit. Getting there means leaning on a 790FX-based motherboard and AMD’s Spider platform. The concept is a new one for AMD. You take AMD’s enthusiast chipset on a third-party motherboard (AMD isn’t manufacturing its own boards) and drop in an AMD processor. Add as many AMD graphics cards as necessary. Finish with the appropriate power, memory, and storage components.

Gigabyte has its own solution for that audience as well. The GA-MA790FX-DQ6 supports a Socket AM2+ Phenom or Athlon 64 chip, up to 16GB of DDR2 memory at 1066 MHz, and the four PCI Express x16 graphics cards you’d hope to see from a high-end enthusiast board. Although subsystem vendor Realtek lends its hand for the HD Audio and Gigabit Ethernet support, the platform is still uniquely AMD’s.

BUDGET GRAPHICS?
Your customer’s biggest concern about a four-card gaming machine is going to be cost. Given that flagship video cards still run as high as $799, that’s an understandable worry. AMD doesn’t charge that much for its boards, though. The company is more focused on capturing the mainstream market.

Play that discrepancy to your advantage. Radeon HD 3850 cards with 256MB of GDDR3 memory are selling all over the place for $169. Four of them, supporting eight monitors, are still a reasonable proposition. And with the performance scaling of four boards as high as 3.2x, according to AMD, there’s more than one good reason to sell the flexibility afforded by CrossFireX.

For further proof of the technology’s incredible scaling, consider AMD’s Radeon HD 3870 X2 with two onboard GPUs and similar frame buffers per processor as existing Radeon cards. Tie two together and you’re looking at the muscle of a four-board solution in a much more elegant package.

NVIDIA FIRES BACK
Given AMD’s new enthusiast platform and Intel’s license to support CrossFire, you’d think that NVIDIA would be in an uncomfortable position. If AMD were shipping the world’s fastest graphics cards, that might be the case. However, NVIDIA’s GeForce 8800 still dishes out the fastest frame rates available from a single board. Power users are still drawn to NVIDIA’s performance message, so resellers courting that upper echelon of power users will want to know it well.

Pursuing the GeForce means making some platform concessions, though. Only NVDIA’s 680i and 780i chipsets support three-way SLI, the latest iteration of a technology used to enable multi-card rendering. Between those two, expect to see more 780i-based platforms because the core logic enables PCI Express 2.0, 45nm Core 2 processor support, and an official 1333 MHz front side bus. Although going with NVIDIA’s 780i means breaking from an Intel chipset and motherboard for your enthusiast systems, the company has a proven track record when it comes to reliability. Customers needn’t worry. What exactly does 3-way SLI bring to the table?

Plain and simple: support for a third graphics card, which NVIDIA claims can scale at up to 2.8x the speed of a single board. Unlike AMD’s CrossFire solution, which works with entry-level and flagship Radeon products, three-way SLI is currently reserved for the GeForce 8800 Ultra and 8800 GTX—NVIDIA’s priciest models.

USE THE FORCE
Let’s say you want to maintain a stable platform image while building on NVIDIA-based product. The idea isn’t a bad one. After all, NVIDIA’s hardware is backed by a renowned unified driver package that simplifies upgrading to and from any combination of nForce or GeForce components. For the reseller, that means less time formatting hard drives and uninstalling driver packages when a customer wants the latest and greatest. It also eases the transition from nForce 600 series to nForce 700 series motherboards in your gaming boxes.

Board partner EVGA recently unveiled its first nForce 780i SLI motherboard built on NVIDIA’s reference design. Naturally, the thing is a beast. Support for any current LGA-775 processor is a given, thanks to a 1333 MHz front side bus setting. Three PCI Express x16 2.0 slots accommodate the latest graphics card configurations, including 3-way SLI. A list of NVIDIA exclusives such as MediaShield storage technology, SLI memory, FirstPacket technology, TCP/IP acceleration, and dual Gigabit Ethernet with teaming highlight a board dripping with enthusiast allure.

Taking full advantage of the platform’s functionality means upselling a trio of GeForce 8800 Ultra or GTX boards, both of which EVGA offers as well. However, you can’t go wrong with a pair of GeForce 8800 GTs either, based on NVIDIA’s G92 core. G92 is architecturally similar to the G80 graphics processor driving most GeForce 8800 series cards. It’s manufactured on a 65nm process and runs at some impressive core frequencies. However, the GeForce 8800 GT card driven by G92 only has one SLI connector, whereas three-way SLI-compatible cards sport two.

PERFORMANCE AT EVERY PRICE
The good news for resellers (along with AMD, NVIDIA, and Intel) is that multi-card graphics configurations aren’t just for the few folks willing to drop thousands of dollars on graphics. CrossFireX, enabled by AMD’s LGA775 chipset and complementary Spider platform, gives you up to eight digital display outputs in addition to the potential for incredible graphics performance. It works with AMD’s fastest graphics cards but also extends down the line to include very affordable mainstream boards. CrossFire on an Intel motherboard delivers the same reliable platform message we keep advocating, with the option for multiple monitors and enhanced graphics processing. You maintain an ecosystem supported by Intel’s powerful reseller program by leveraging graphics technology officially blessed by Intel on its best desktop chipsets.

NVIDIA’s three-way SLI technology reaches the most discerning buyers who are only satiated by bleeding edge hardware. Of course, two-card tech continues to be one of the most elegant ways to get a pair of graphics cards working in concert, so use the GeForce 8800 GT and mid-range AMD options for affordable plays here. Whether your customer needs three-way SLI for highend gaming or AMD’s CrossFireX for everything else, selling motherboards with multiple PCI Express x16 slots lays the groundwork for unprecedented scaling as your customer’s graphics demands change.