As in this question: Ubuntu 17.10: high CPU usage by gnome-shell 3.26.1, and this question gnome-shell 3.26.1 constantly uses 20-30% CPU, I also have an issue where gnome-shell is constantly above 20% CPU, even with nothing other than terminal open:

$ top

....

 8029 xxxxxx    20  10 1714052 601696  54568 R  46.1 15.0   1179:08 gnome-shell

....



$ lspci | grep -i vga

00:02.0 VGA compatible controller: Intel Corporation Atom Processor 

Z36xxx/Z37xxx Series Graphics & Display (rev 0e)



$ glxinfo | grep -i render

direct rendering: Yes

    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer, 

    GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer, 

Extended renderer info (GLX_MESA_query_renderer):

OpenGL renderer string: Mesa DRI Intel(R) Bay Trail x86/MMX/SSE2

    GL_ARB_compute_shader, GL_ARB_conditional_render_inverted, 

    GL_MESA_texture_signed_rgba, GL_NV_conditional_render, GL_NV_depth_clamp, 

    GL_ARB_compute_shader, GL_ARB_conditional_render_inverted, 

    GL_NV_conditional_render, GL_NV_depth_clamp, GL_NV_light_max_exponent, 

    GL_OES_element_index_uint, GL_OES_fbo_render_mipmap, 

I have gnome-tweak-tool installed, but I have no extensions running (I've disabled them through the menu).

Is there any way of reducing the background gnome-shell CPU usage to something sensible? At the moment I can't have a browser open, a terminal open and Dropbox syncing without the load average reaching 6+, slowing everything down.

EDIT: I've dodged the problem by logging into Unity not GNOME with Wayland or GNOME with xorg, but this is not a long-term solution, as Unity is being phased out.