This indicates the proportion of the graphics card memory that is currently used.
This indicator should always remain green.
If it turn
go to How-to Manage Loading and VRam usage
for optimizing your show.
Here is a list of tips to reduce the amount of used GPU memory:
GPU Memory is shared between all applications, so first, close other applications that may be using the graphics card.
Close documents in Smode you don't use
Toggle the ON-AIR button twice (this will cleanup unused memory resources)
Lower your compo/texture resolutions
Reduce the multi-sampling parameters if you used it
If nothing else works, simplify your compo and use less images, videos and pre-compositions
See Use optimisation tools to accelerate a composition
for more tips on optimization of content in Smode.