diff --git a/doc/configuration.txt b/doc/configuration.txt
index 8ba4ce897..e8e54a31d 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -2267,7 +2267,11 @@ thread-group <group> [<thread-range>...]
 thread-groups <number>
   This setting is only available when support for threads was built in. It
   makes HAProxy split its threads into <number> independent groups. At the
-  moment, the limit is 1 and is also the default value. See also "nbthread".
+  moment, the default value is 1. Thread groups make it possible to reduce
+  sharing between threads to limit contention, at the expense of some extra
+  configuration efforts. It is also the only way to use more than 64 threads
+  since up to 64 threads per group may be configured. The maximum number of
+  groups is configured at compile time and defaults to 16. See also "nbthread".
 
 uid <number>
   Changes the process's user ID to <number>. It is recommended that the user ID
diff --git a/include/haproxy/defaults.h b/include/haproxy/defaults.h
index 21aae896d..6dc5167d8 100644
--- a/include/haproxy/defaults.h
+++ b/include/haproxy/defaults.h
@@ -39,9 +39,14 @@
 #define MAX_THREADS LONGBITS
 #endif
 
-/* still limited to 1 group for now by default (note: group ids start at 1) */
+/* theoretical limit is 64, though we'd rather not push it too far for now
+ * as some structures might be enlarged to be indexed per group. Let's start
+ * with 16 groups max, allowing to experiment with dual-socket machines
+ * suffering from up to 8 loosely coupled L3 caches. It's a good start and
+ * doesn't engage us too far.
+ */
 #ifndef MAX_TGROUPS
-#define MAX_TGROUPS 1
+#define MAX_TGROUPS 16
 #endif
 #define MAX_THREADS_PER_GROUP LONGBITS
 #endif