# Some question about multiple graphics cards

**URL:** <https://discourse.slicer.org/t/some-question-about-multiple-graphics-cards/21072>\
**Category:** Support\
**Created:** [December 15, 2021, 8:25am UTC](https://discourse.slicer.org/t/some-question-about-multiple-graphics-cards/21072 "2021-12-15T08:25:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![476663616](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/476663616/32/12994_2.png) [@476663616](https://discourse.slicer.org/u/476663616)\
**Post date:** [December 15, 2021, 8:25am UTC](https://discourse.slicer.org/t/some-question-about-multiple-graphics-cards/21072/1 "2021-12-15T08:25:48Z")

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My lab has a server with multiple graphics cards. I am doing machine learning related operations, but slicer seems to work on graphics card 0 by default. Recently, many people are running programs, and my Slicer always prompts out of memory. How can I change the working graphics card of the Slicer?  
 ![1639556471(1)](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/0/4/04b750152dae2b4ec34342a7dc0e7e95f7e78c98.png)  
I have tried the code:CUDA\_VISIBLE\_DEVICES=1, but it seems to help nothing…

Thanks for any help!

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [December 15, 2021, 1:47pm UTC](https://discourse.slicer.org/t/some-question-about-multiple-graphics-cards/21072/2 "2021-12-15T13:47:12Z")

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For graphics operations Slicer will use the card that’s configured for the X server (e.g. in xorg.conf). If you are running cuda or other GPU code in Slicer you can select whichever devices are detected by the drivers.