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I've been using Blender for a few months now and I am not entirely sure I am taking full advantage of my two GPUs.

I have MacOS Sierra, Windows 10, and Ubuntu installed on my machine all with the latest CUDA Drivers, and 2 GeForce 1050 ti SC 4gb GPUs installed.

Rendering times compared to my 15'MBP i7 CPU are obviously better but I am wondering if there is something missing. The smoothest and fastest experience with almost no crashes on Blender 2.78c is surprisingly in MacOS Sierra.

I've got both GPUs selected in Blender > UserPreferences > System and with most scenes I stick to 256 x 256 in performance. I also noticed that Blender Cycles renders one tile at a time, and I was under the impression that with 2 GPUs, 2 tiles would be rendered at a time.

Then again I think this might be due to the system seeing the GPUs as one unit. I should mention that iStat software reads both GPU processors being used just fine, but I thought I should ask anyway.

Any advice or hints that you can recommend are greatly appreciated, thanks for listening.

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  • $\begingroup$ You mention selecting both cards in preferences so if both cards are there to choose then blender sees both. To be only rendering one tile at a time, I would check the thread settings in the performance tab. $\endgroup$ – sambler Jul 30 '17 at 5:26
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Are your GPUs in SLI or similar pairing technology, or somehow presented at OS level as a single GPU?

If so that will negatively affect performance in Blender, because those systems are generally inefficient and will not fully utilize the power of both GPUs fully.

Blender however if presented with two discrete graphics cards for rendering in Cycles can make fll use of both at full speed without performance compromises, virtually doubling the speed and halving render time.

Having only one bucket while rendering is generally a sign that only one GPU is being detected by Cycles.

If possible tweak your settings in such way that Blender can see both your graphics cards as independent hardware.

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