The results are quite interesting and of course that they depend on the actual hardware used:
B4J - more than 20,000 boxes
B4A (Nexus 5X) - 1,000 boxes
B4i (iPhone 8+) - 20,000 boxes
B4i result is a bit surprising. It is related to the performance improvements done in B4i v5.0.
Note that the boxes are drawn with SkipBlending = True. It will be much slower with blending (blending means that transparent parts and semi-transparent parts of the drawn image are blended with the current pixel color).