diff --git a/doc/doxygen.conf b/doc/doxygen.conf
index c90c3c1e9..7b1624bc2 100644
--- a/doc/doxygen.conf
+++ b/doc/doxygen.conf
@@ -466,7 +466,7 @@ TYPEDEF_HIDES_STRUCT   = YES
 # the optimal cache size from a speed point of view.
 # Minimum value: 0, maximum value: 9, default value: 0.
 
-LOOKUP_CACHE_SIZE      = 1
+LOOKUP_CACHE_SIZE      = 2
 
 # The NUM_PROC_THREADS specifies the number threads doxygen is allowed to use
 # during processing. When set to 0 doxygen will based this on the number of
@@ -479,7 +479,7 @@ LOOKUP_CACHE_SIZE      = 1
 # DOT_NUM_THREADS setting.
 # Minimum value: 0, maximum value: 32, default value: 1.
 
-NUM_PROC_THREADS       = 1
+NUM_PROC_THREADS       = 0
 
 #---------------------------------------------------------------------------
 # Build related configuration options