I understand that the way moving the triangle directly in the CPU is not a good way. But the strange thing is that I can't reprocedure the efficiency problem on the same computer again. I can only believe that this is just my illusion.(Maybe I'm running my computer on powersaving mode?)
Another problem is that when I run two OpenGL applications and enable v-sync, the FPS will drop to 30 and application becomes a little lag. Is there a solution to this problem?