diff -r 263a354329e9 -r b3efd7552d83 etc/settings
--- a/etc/settings	Thu Sep 10 11:03:29 2015 +0200
+++ b/etc/settings	Thu Sep 10 11:47:14 2015 +0200
@@ -40,7 +40,7 @@
 ISABELLE_BUILD_OPTIONS=""
 
 ISABELLE_BUILD_JAVA_OPTIONS32="-Djava.awt.headless=true -Xms128m -Xmx1024m -Xss1m"
-ISABELLE_BUILD_JAVA_OPTIONS64="-Djava.awt.headless=true -Xms512m -Xmx4096m -Xss4m"
+ISABELLE_BUILD_JAVA_OPTIONS64="-Djava.awt.headless=true -Xms512m -Xmx2560m -Xss4m"
 
 
 ###