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Linkboost

With the 590, NVIDIA are turning to the most seemingly small tweak for every ounce of performance they can find. As briefly explained earlier, Linkboost overclocks the PCI-E x16 slots and HT link between the SPP and MCP. These busses are both overclocked by 25%, theoretically increasing performance by removing any information transfer bottlenecks -- but the question is whether these information highways are bottlenecked to start with. What is important to note about LinkBoost is that it is only enabled when a GeForce 7900 GTX card (or two) is installed.

This decision on the part of NVIDIA makes sense simply because the 7900 GTX is one of a small handful of cards (picking from only NVIDIA cards narrows it even further) that is powerful enough to stand a chance at saturating the PCI-Express bus, though even that is debatable.

We benchmarked three popular games with LinkBoost enabled and disabled, with and without SLI, in order to sneak a peek at what LinkBoost may offer. The results are as follows:

As you can see, LinkBoost brings some minimal performance gains, though primarily at lower resolutions. This is because the GPU is able to render the frames passed to it far more quickly at these resolutions, thus requiring the movement of data between the GPU and CPU to keep pace. Overclocking the two busses removes the (minimal) bottleneck that is created as a result of the lower resolution. Suffice it to say, anyone running a 7900 GTX is unlikely to be playing games at anything less than 1024 x 768, making the benefits of LinkBoost negligible. However, as futureproofing for next generation graphics chips which may require more from the two interconnects, LinkBoost is a great feature.

GPU Ex

Another feature that NVIDIA seems to be neglecting to widely publicize is an option in the BIOS called "GPU Ex". We can only assume that this is enabling some driver-level optimizations as it requires a 90-series driver to be installed for it to work. To satisfy our curiosity, we ran a similar set of benchmarks with and without GPU Ex turned on. Let's take a look:

Nothing astounding, but notable nonetheless. We wish we could provide you with specifics as to the function of the "GPU Ex" option, but NVIDIA has not been clear as of yet.

Moving on!