This window allows you roughly estimate your hardware performance. It simply redraws the plot in cycle (number of cycles should be increased to make test results more reproducible). Performance tester has two modes: processor-intensive (string expression parsed to calculate point coordinates) or video-intensive (more GDI calls are used to draw curve). For comfortable work with DM2000 your computer must be at least more quick then my old Pentium 120 MHz!
Note that these tests give you only approximate value of computer performance, and "processor test" strongly depends on the installed video card; however, it shows real DM2000 application productivity.