diff --git a/src/framerate_gui.cpp b/src/framerate_gui.cpp
--- a/src/framerate_gui.cpp
+++ b/src/framerate_gui.cpp
@@ -965,7 +965,7 @@ struct FrametimeGraphWindow : Window {
 					(int)Scinterlate<int64>(x_zero, x_max, 0, (int64)draw_horz_scale, (int64)draw_horz_scale - (int64)time_sum),
 					(int)Scinterlate<int64>(y_zero, y_max, 0, (int64)draw_vert_scale, (int64)value)
 				};
-				assert(newpoint.x <= lastpoint.x);
+				if (newpoint.x > lastpoint.x) continue; // don't draw backwards
 				GfxDrawLine(lastpoint.x, lastpoint.y, newpoint.x, newpoint.y, c_lines);
 				lastpoint = newpoint;