diff --git a/developer-workflow/extension-modules.rst b/developer-workflow/extension-modules.rst
index 61c1ff08a..d6be88824 100644
--- a/developer-workflow/extension-modules.rst
+++ b/developer-workflow/extension-modules.rst
@@ -547,8 +547,11 @@ Now that the configuration is in place, it remains to compile the project:
 
 .. tip::
 
-   Use ``make -j`` to speed-up compilation by utilizing as many CPU cores
-   as possible or ``make -jN`` to allow at most *N* concurrent jobs.
+   Use ``make -jN`` to speed-up compilation by utilizing as many CPU cores
+   as possible, where *N* is as many CPU cores you want to spare (and have
+   memory for). Be careful using ``make -j`` with no argument, as this puts
+   no limit on the number of jobs, and compilation can sometimes use up a
+   lot of memory (like when building with LTO).
 
 * ``make regen-configure`` updates the :cpy-file:`configure` script.
 
diff --git a/index.rst b/index.rst
index 9dbc06908..58d4deca7 100644
--- a/index.rst
+++ b/index.rst
@@ -43,13 +43,13 @@ instructions please see the :ref:`setup guide <setup>`.
 
       .. code-block:: shell
 
-         ./configure --with-pydebug && make -j
+         ./configure --with-pydebug && make -j4
 
    .. tab:: macOS
 
       .. code-block:: shell
 
-         ./configure --with-pydebug && make -j
+         ./configure --with-pydebug && make -j4
 
    .. tab:: Windows