diff --git a/src/Viewer/renderer.cxx b/src/Viewer/renderer.cxx
index 807a62fbe..0a3701d32 100644
--- a/src/Viewer/renderer.cxx
+++ b/src/Viewer/renderer.cxx
@@ -479,6 +479,9 @@ FGRenderer::init( void )
         }
         else {
             composite_viewer = new osgViewer::CompositeViewer;
+            bool use_affinity = fgGetBool("/sim/thread-cpu-affinity", true);
+            SG_LOG(SG_GENERAL, SG_ALERT, "Calling composite_viewer->setUseConfigureAffinity() with use_affinity=" << use_affinity);
+            composite_viewer->setUseConfigureAffinity(use_affinity);
         }
         
         // https://stackoverflow.com/questions/15207076/openscenegraph-and-multiple-viewers