My Visual Studio 2019, 64-bit version of Tetris using OpenGL runs significantly faster, 3X, in Debug mode than in Release mode.
The image above shows the board. Each cycle of the rendering or game loop redraws everything, viz., the light blue background, the grid, the individual game pieces (one shown) with the latest one added moving every 300 ms, and the text score display. I have moved all the repetitive code out of the loop, e.g., that which sets the location in shaders for uniform constants.
The Release mode loop cycle time ranges from 0.05 to 1390.0 ms while that of the Debug mode ranges from 0.05 to 350.0 ms.
Any thoughts on what I might investigate?