diff --git a/tbsetup/libvtop_test.pm.in b/tbsetup/libvtop_test.pm.in
index 75ba278835db45f9e16c2c2b427810e7a9b50716..c21912f4adadeafc7c9bc020f5fb537c4ecf16ec 100755
--- a/tbsetup/libvtop_test.pm.in
+++ b/tbsetup/libvtop_test.pm.in
@@ -1423,8 +1423,8 @@ sub LoadVirtNodes($)
 
 	    if (defined($vnode->_parent_osinfo())
 		&& $vnode->_parent_osinfo()->osname() =~ /xen/i) {
-		$defmem = 256;
-		$minmem = 192;
+		$defmem = 512;
+		$minmem = 256;
 		$maxmem = 1024;
 	    }	    
 	    if (!exists($vnode->_desires()->{"?+ram"})) {