My graphics card (geforce gtx 1070) actually supports this big volume, but the customer gpu probably will not support these dimensions.
The rendering speeds for 4112x3008x32 are as follow:
whole volume with vtkOpenGLGPUVolumeRayCastMapper : ~150fps
whole volume with vtkOpenGLGPUVolumeRayCastMapper and SetPartitions(2, 2, 2) : ~3fps
partitioned volume with vtkMultiBlockVolumeMapper 2x2x2 : ~70fps