Blender closes when rendering I just started learning blender and I have a problem when rendering my model. Sometimes when I change my viewport shading to rendered my Blender closes.

Here is my settings:
Cycles render
Device: GPU Compute
And I also set my system preference to Open CL > Tahiti

My computer specs:
CPU - AMD FX-6300
GPU - R9 280X

But when I rendered it using CPU it does work properly. Sometimes it also works using GPU, I don't really know what's the problem.
OpenCL rendering with Cycles is relatively young in Blender and largely experimental at this point. It is still feature limited, unstable, and prone to crashing as it currently stands.

Can you provide a blend file that crashes?

Try upgrading your graphics drivers, restarting and see if the situation improves. Otherwise it is probably a bug and should be reported in the bugtracker.