ASUS STRIX GTX 780 OC 6GB Overclocking Review

We take the new ASUS STRIX GTX 780 OC 6GB video card and push it to its limits while overclocking. We will compare performance overclocked with a GeForce GTX 780 Ti, AMD Radeon R9 290X and find out what gameplay improvements overclocking allows. This card isn't just silent, its got overclocking prowess too.


Overclocking without Voltage

Let's first start by showing you what was achieved without changing voltage or fan speed. For this overclocking test we left the voltage at default, and we even left the fan at default "Auto" setting. In this way we can find the best overclock still with a quiet sound profile in mind using the STRIX technology to control the fan speeds.

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We did increase the Power Target and GPU Temp Target to their maximum values. We managed to push the base clock up to 1048MHz and the boost clock to 1100MHz. This resulted in an actual in-game clock speed of 1215MHz. Keep in mind this is with the fan speed on "Auto." We managed to push the memory up to 6.6GHz.

As you can see in the GPUz screenshot 1215MHz was achieved consistently, with no fluctuations while gaming. This is an impressive 157MHz overclock from the default 1058MHz without even touching the voltage. This was just a simple GPU clock offset increase, that's all, we didn't even touch the fans.

In the GPUz screenshot you can see the fans automatically ramped up to a maximum of 56% while gaming, only about half of the total capable fan speed! What's more the temperature at only about half fan speed was 74c at 1215MHz.

For comparison, without overclocking, the fan speed went up to only 49% fan speed and kept the GPU at 73c. Therefore, running at 1215MHz did require the fans to run 14% faster, but by doing so the temperature was only one degree hotter than running at default clock speed of 1058MHz. This shows how well the DirectCU II cooling solution implemented by ASUS is doing to keep the GPU cool at low fan speeds.

You can see the voltage was running at the default 1.1620V here and the TDP is 110% instead of the default 100%. Power demand at this setting was 431W from the system, which is up from 402W at default settings.

Overclocking with Voltage Increase

Now it is time to max out the ASUS STRIX GTX 780 OC 6GB and increase voltage and fan speed to find out the limits of this GPU. GPU Tweak allows us to increase the slider to 1.212V, however, this was not exactly what we got in the real-world as you will see below.

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The maximum voltage we could obtain in reality turned out to be 1.1870V. This is certainly higher than the 1.1620V we get at default settings, and it did lead to a higher overclock. We do believe though that if we could truly get the advertised in GPU Tweak 1.212V our achievable overclock would indeed be higher than it is at 1.1870V. It would also demand a lot more from the cooling solution, but we think there is room in the DirectCU II cooling solution for that as you can see from the temperature of the GPU with 100% fan turned on while overclocked.

We managed to push the base clock up to 1078MHz and the boost clock up to 1130MHz. This resulted in an actual in-game frequency of 1254MHz. This is a 39MHz overclock from the 1215MHz without changing voltage. This is a 196MHz overclock from the default speeds of 1058MHz, which is quite impressive. We actually managed to get the clock speed all the way up to 1280MHz in one game, and it was stable. However, in the other games it causes crashing. When we lowered the GPU Boost to 1130MHz which resulted in 1254MHz it was stable in all games. The memory was again able to reach 6.6GHz.

What is impressive is the GPU temperature with 100% fan. The GPU temperature while overclocked at 1254MHz was 60c. This is 15 degrees cooler than the default temp or overclocked on auto fan with no voltage temp. This shows us that the GPU is plenty cool and that the DirectCU II cooler is not holding back our overclock. Temperature and heat is not the issue for reaching higher clock speeds with this GPU. We are limited by the voltage and natural properties of the GPU on the video card.

You can see the maximum voltage of 1.1870V achieved and a TDP of 116% which shows we are pushing this card to the bleeding edge of what it can do. The power consumption at this setting is 442W for the system.

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Here is a summary of how the overclock breaks down.

Test Setup

On the following pages we will look at the performance advantages the overclocking provides. All test setup and drivers are exactly the same as our original evaluation as outlined here.