diff --git a/src/StaticPHP/Command/Dev/GenExtTestMatrixCommand.php b/src/StaticPHP/Command/Dev/GenExtTestMatrixCommand.php
index 2587df7d..ffc94b52 100644
--- a/src/StaticPHP/Command/Dev/GenExtTestMatrixCommand.php
+++ b/src/StaticPHP/Command/Dev/GenExtTestMatrixCommand.php
@@ -11,7 +11,7 @@ use Symfony\Component\Console\Attribute\AsCommand;
 #[AsCommand('dev:gen-ext-test-matrix', 'Generate GitHub Actions extension test matrix JSON', [], true)]
 class GenExtTestMatrixCommand extends BaseCommand
 {
-    private const BUILD_TARGETS = '--build-cli --build-cgi --build-micro';
+    private const BUILD_TARGETS = '--build-cli --build-cgi --build-micro --dl-parallel=10';
 
     private const OS_RUNNERS = [
         'linux' => ['arch' => 'x86_64', 'runner' => 'ubuntu-latest', 'os_key' => 'Linux'],