Overclocking, Noise, Temperature And Power
When it comes to overclocking, nothing beyond the factory frequencies are guaranteed. Picking a card like Gigabyte's GeForce GTX 950 Xtreme Gaming, which sports a cherry-picked GPU, certainly helps. But it still comes down to the silicon lottery.
OC Guru II
My go-to utility for overclocking graphics cards is MSI's Afterburner, which was designed to support almost any GPU. But when companies go through the effort of creating their own tools, I like to give them a shot.
Gigabyte provides OC Guru II with its GeForce GTX 950 Xtreme Gaming card. This software lets you monitor temperatures, clock rates, voltage levels and fan speeds. OC Guru II also enables GPU clock, memory clock, core voltage and fan speed adjustments. Plus, it gives you control over the Windforce logo's LEDs.
Much like Afterburner, OC Guru II lets you adjust the GPU and memory frequencies in granular steps. Every click on the arrow buttons move the clock rate by 1MHz, and voltage adjustments are applied in 0.0125V increments.
Unlike most GPU overclocking tools, the temperature and power target values are not linked by default. You're able to increase the power target an additional eight percent, and the temperature can be increased by 15 degrees Celsius to a threshold of 95 degrees. Either option can be maxed out without affecting the other. OC Guru can also be configured to prioritize the GPU temperature over the power limit.
To overclock Gigabyte's GeForce GTX 950 Xtreme Gaming, we first adjusted the power limit. We didn't bother with the temperature limit because the GPU wasn't even approaching 80 degrees under extreme load. From there, we played with the core clock in 5MHz increments until the card crashed, after which point we used single-MHz tweaks. Ultimately, we saw stability at 1273MHz, or 70MHz higher than Gigabyte's shipping frequency. Increasing the voltage a few notches proved to be no help in achieving higher clock speeds.
Gigabyte includes the same memory found in Nvidia's GeForce GTX 960 specification. With the GDDR5 already running at its peak rate, overclocking was bound to be a struggle. In the end, we achieved an additional 20MHz.
The overclocked settings were stable, except for in Shadow of Mordor. For some reason, that title penalizes our tuned configuration with lower performance than the factory setup. There were no crashes or artifacts, just a lower frame rate.
Noise, Power and Temperature
Gigabyte's GTX 950 may have outperformed Asus in the gaming tests, but if you want the quietest card available, Gigabyte does fall short. A reading of 39 decibels is certainly not loud, and you probably won't notice it. However, the measurement is still higher than Asus' card.
Interestingly, before the driver was installed, the card's fans were spinning particularly quickly, causing a slight "tinging" sound. There were no indications of a loose component or bad bearing, so I suspect it was caused by vibrations from wind turbulence. During normal operation, this behavior was not observed.
The power consumption numbers were a little bit surprising. The consequence of overclocking was expected, but presenting the lowest idle consumption figure at stock speeds was not. Under load, Gigabyte's card uses quite a bit of power. At idle, though, it registers 1.5W less than Asus' GTX 950 Strix.
Gigabyte's Windforce cooling solution does a great job keeping the GPU temperature under control. During a 10-minute run of Battlefield 4, the processor barely crept up over the 60-degree mark. Curiously, the GPU on Gigabyte's card heated up rapidly and then stabilized once the fan kicked on. In contrast, the GTX 950 Strix took a couple of minutes to heat up, after which it maintained a higher peak temperature.
Even after we applied our overclocked settings, the GeForce GTX 950 Xtreme Gaming managed to hold essentially the same temperature pattern through the test.