diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1900213b48..e419159969 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -399,9 +399,9 @@ installation:
     - cp -r "src/python/object_in_fluid" "${CI_INSTALL_PYTHON_PATH}/object_in_fluid"
     # run all tests with the installed files
     - sed -i "s|$(pwd)/pypresso|${CI_INSTALL_DIR}/bin/pypresso|" testsuite/{python,scripts/samples,scripts/tutorials}/CTestTestfile.cmake
-    - make -j ${CI_CORES} check_python_skip_long
-    - make -j ${CI_CORES} check_samples
-    - make -j 2 check_tutorials
+    - make check_python_skip_long
+    - make check_samples
+    - make check_tutorials
   tags:
     - espresso
     - cuda