Iray is using my GPU but Shouldn't be...

heinzerbrew_f94794efff

I have a 1050 ti which has 4 GB of memory. Until today if the memory is exceeded, rendering is cpu only.

This scene seems to need at least 7.5 GB.

Here are some snippets from my log.

CUDA device 0 (GeForce GTX 1050 Ti): out of memory (while allocating memory)
CUDA device 0 (GeForce GTX 1050 Ti): Failed to allocate 875.653 MiB

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Device statistics:
rend info : CUDA device 0 (GeForce GTX 1050 Ti):      1268 iterations, 96.480s init, 7108.885s render
CPU:      302 iterations, 93.321s init, 7111.289s render

My hardware monitor shows the Geforce card is being maxed out on the processor and only 80 percent of its memory is being used.

I had messed with this scene several times trying to eliminate textures and objects to get the size down but it always went to cpu only. So I gave up and decided to just let it do the whole scene on cpu instead of trying to photoshop a bunch of layers together.

Now the GPU is rendering a scene that I didn't think it could and that I couldn't render 3 hours ago. Did I stumble on to some magic or am I crazy?