GPU Boost 2.0: Changing A Technology’s Behavior
GPU Boost is Nvidia’s mechanism for adapting the performance of its graphics cards based on the workloads they encounter. As you probably already know, games exact different demands on a GPU’s resources. Historically, clock rates had to be set with the worst-case scenario in mind. But, under “light” loads, performance ended up on the table. GPU Boost changes that by monitoring a number of different variables and adjusting clock rates up or down as the readings allow.
In its first iteration, GPU Boost operated within a defined power target—170 W in the case of Nvidia’s GeForce GTX 680. However, the company’s engineers figured out that they could safely exceed that power level, so long as the graphics processor’s temperature was low enough. Therefore, performance could be further optimized.
Practically, GPU Boost 2.0 is different only in that Nvidia is now speeding up its clock rate based on an 80-degree thermal target, rather than a power ceiling. That means you should see higher frequencies and voltages, up to 80 degrees, and within the fan profile you’re willing to tolerate (setting a higher fan speed pushes temperatures lower, yielding more benefit from GPU Boost). It still reacts within roughly 100 ms, so there’s plenty of room for Nvidia to make this feature more responsive in future implementations.
Of course, thermally-dependent adjustments do complicate performance testing more than the first version of GPU Boost. Anything able to nudge GK110’s temperature up or down alters the chip’s clock rate. It’s consequently difficult to achieve consistency from one benchmark run to the next. In a lab setting, the best you can hope for is a steady ambient temperature.
Vendor-Sanctioned Overvoltage?
When Nvidia creates the specifications for a product, it targets five years of useful life. Choosing clock rates and voltages is a careful process that must take this period into account. Manually overriding a device’s voltage setting typically causes it to run hotter, which adversely effects longevity. As a result, overclocking is a sensitive subject for most companies—it’s standard practice to actively discourage enthusiasts from tuning hardware aggressively. Even if vendors know guys like us ignore those warnings anyway, they’re at least within their right to deny support claims on components that fail prematurely due to overclocking.
Now that GPU Boost 2.0 is tied to thermal readings, the technology can make sure GK110 doesn’t venture up into a condition that’ll hurt it. So, Nvidia now allows limited voltage increases to improve overclocking headroom, though add-in card manufacturers are free to narrow the range as they see fit. Our reference GeForce GTX Titans default to a 1,162 mV maximum, though EVGA’s Precision X software pushed them as high as 1,200 mV. You are asked to acknowledge the increased risk due to electromigration. However, your warranty shouldn’t be voided.
