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Since a lot of you are asking about GPU rendering (and the NVIDIA GeForce cards have become so popular for rendering) we decided to compare the current high-end GeForce cards using a more realistic benchmark than the exterior car scenes which have become so commonplace.

When it comes to GPU rendering, it doesn't get more real than Kevin Margo's short film CONSTRUCT which was rendered on a BOXX GPU-dense workstation using V-Ray RT. Thanks to our friends at Chaos Group, we were able to get our hands on one of Kevin’s 3ds Max CONSTRUCT scene files for some testing. In this article, we’ll discuss the pros and cons of using high-end GeForce GTX cards for final frame production rendering.

Rendering Performance

Let’s get right down to it and talk about render times. The chart below compares the average render time of nine frames in an animated sequence. There were ten total frames in the test sequence and for each, the first frame was discarded because it was significantly faster than the subsequent frames. The GPU was cooler on the first frame, yielding a faster than average result. But as the card reached temperature, there were consistent render times going forward.

renderGraph

The GTX Titan Black became the champion in our tests, besting the GTX 980 and 970. Given the new Maxwell GPU compute architecture available in the NVIDIA 900 series, we expected the GTX 980 to put up a stronger fight, however, the 980 and 970 still posted respectable times. Below is a wireframe of the scene used in the tests.

Note: It is still a bit early to pass full judgement on the performance the 900 series Maxwell based GTX cards. Future updates to V-Ray as well new NVIDIA drivers could significantly improve the results above.

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What GPU specifications should you look for?

For GPU rendering, you want as many CUDA cores as your budget allows. With that understanding, the Titan Black continues to lead the GeForce lineup by a wide margin. If you compare the chart above to the one located below, it’s easy to appreciate the relationship between CUDA cores and rendering performance.

cudaCores

Despite the importance of CUDA cores, they aren’t the only spec you should consider. Because all of your scene’s assets (including the scene file, textures, etc.) need to fit within the GPU’s memory, you need to make sure that the GPU you choose can accommodate your dataset. For most users this isn’t an issue, especially if you opt for the Titan Black with 6GB of memory. But for some, the 4GB memory limit of the 980 and 970 may be too constricting.

Which is most cost effective?

Based on the chart above, we know that the amount of CUDA cores on board has the greatest influence on render times. Therefore, if you want the most compute power for your money, you should think about how much you are paying per CUDA core. The GTX 970 at just 21 cents/CUDA is the best overall value if you on a strict cost consideration.

That said, many artists want a higher compute capability than a single GTX 970 has to offer. If your goal is compute density (packing as many CUDA cores in a machine as possible) then cards like the 980 and Titan become more favorable.

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Pros and Cons

GTX Titan
Pro - Most CUDA cores and large memory footprint.
Cons – Most expensive GTX card. Higher upfront cost. Highest price/CUDA core.

GTX 980
Pro – Respectable amount of CUDA cores ( 2048). Lower upfront cost.
Cons – High price/CUDA core. Lower memory footprint.

GTX 970
Pro – Low upfront cost. Cheapest price/CUDA core.
Cons - Lower memory footprint. Low compute density.

Choosing a the right workstation

If you’re ready to dive into GPU rendering, you won’t find a better workstation solution than the BOXX APEXX 4 which supports up to four full-size GPUs. To learn more, watch the video here.

If you wish to speak with a BOXX performance specialist, please complete the form here.