I have no idea what "scriched" means. You have nothing in your timeline. The green bar shows how much of the timeline is loaded into ram. With the default Preferences settings and Preview settings, nothing will load into ram until you start a preview or drag the CTI around the timeline. The duration of the ram preview depends on the frame size of the composition, the frame rate of the composition, and the Composition Panel resolution. Your Composition Panel Magnification Ratio is telling me that the comp frame size is probably 4K, and that will limit the duration of your playback.
Looks normal, given how RAM previews work. Your screenshot shows around 45 seconds of previewable time, which could be as good as it gets on your system, depending how much memory you actually have. I think you may simply need to read up on how previews in AE work and manage your expectations.