diff --git a/defaults/main.yml b/defaults/main.yml
index 825107a..b9ab81b 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -76,7 +76,7 @@ repo_build_uca_enable: True
 uca_apt_repo_url: "http://ubuntu-cloud.archive.canonical.com/ubuntu"
 
 repo_build_timeout: 120
-repo_build_concurrency: "{{ ansible_processor_count if ansible_processor_count > 0 else 5}}"
+repo_build_concurrency: "{{ (((ansible_processor_vcpus|default(1)) | int) > 4) | ternary(8, 4) }}"
 repo_build_venv_build_dir: "/tmp/openstack-venv-builder"
 repo_build_venv_dir: "/var/www/repo/venvs"
 repo_build_venv_pip_install_options: >