MSI Eclipse Plus: Does nForce 200 Boost 3-Way SLI?

The question for Nvidia almost certainly began with “what to do about QPI?”

Formerly a major player in the high-end Intel chipset market, Nvidia hasn't yet said anything about supporting the latest generation of processor technology. In the past, the company has used SLI as the juciest carrot to get enthusiasts onboard with its core logic. However, with Intel manufacturing the only Core i7-compatible chipset, Nvidia first decided it would require an additional hardware component, the nForce 200 PCI Express bridge, to be present on any Intel Core i7 motherboard before SLI could be enabled. Manufacturers protested, while review sites pointed out that a software lock was all that prevented SLI from working on any PCI Express chipset. Nvidia quickly did an about-face and was soon licensing a BIOS-based “hook” that determined SLI eligibility.

But was this really such a big win for consumers? The only available Core i7 chipset, Intel’s X58 Express, has 36 PCI Express lanes, and quick math shows that having two native x16 slots allows only x4 lane width to a third graphics card. Another option that motherboard vendors have taken is to split one of the x16 slots into two x8 pathways, to provide an x16-x8-x8 configuration in 3-way SLI.

There is, however, a third option: the PCI Express component that Nvidia originally wanted to see down on X58-based platforms. By adding a controller like Nvidia’s nForce 200, motherboard manufacturers can claim a full sixteen pathways on all three x16 slots, (even though two of the three slots must share bandwidth). Such a hub could theoretically spread identical data across both slots at full bandwidth, though we’ve yet to see any practical demonstration showing that this happens and indeed helpe improve performance.

Moving beyond theory, smart hubs can redistribute bandwidth on the fly to allow one device to receive full bandwidth when the other is idle. Hubs do add latency, but the nForce 200 is purportedly both smart and low-latency.

Theories and claims aside, practical performance is what really matters. Using a powerful 3-way SLI graphics solution provided by EVGA, we compared MSI’s nForce 200-equipped Eclipse Plus motherboard to x16-x8-x8 and x16-x16-x4 motherboards from rival Asus.