This back-end allocates the memory required for the surface directly in RAM. On Windows / VCL it does not acquire any GDI handles or resources.
It does not support any of the interfaces required for TBitmap32, making it lightweight but also feature limited. Temporarily switching to a more sophisticated back-end like TGDIBackend can alleviate this problem.
TMemoryBackend is the default back-end of TCustomBitmap32.
[See also]