Tried out Doug Sawatzky's settings, and checked out the scenery library. In the scenery library everything is checked (some are greyed checked) except for a few scenery addons I have so that I can gain a little more performance. Unfortunately the white lines are still appearing. Even pausing the sim for 10 seconds like Aussie123 did, they don't heal. I've also included my AMD Radeon graphic settings if that's any helpful. The first two, from what I'm assuming, is specifically for P3D Gameplay. The others is for general use.