diff --git a/.circleci/config.yml b/.circleci/config.yml
index e8e451eee..822903587 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -58,7 +58,7 @@ jobs:
             - /usr/local/bin/phantomjs
   test:
     <<: *defaults
-    parallelism: 3
+    parallelism: 4
     steps:
       - checkout
       - *install_system_deps