diff --git a/src/Symfony/Component/Process/ProcessPipes.php b/src/Symfony/Component/Process/ProcessPipes.php
index f35d1c1287..8b11a930fc 100644
--- a/src/Symfony/Component/Process/ProcessPipes.php
+++ b/src/Symfony/Component/Process/ProcessPipes.php
@@ -284,6 +284,8 @@ class ProcessPipes
     private function readStreams($blocking, $close = false)
     {
         if (empty($this->pipes)) {
+            usleep(Process::TIMEOUT_PRECISION * 1E4);
+
             return array();
         }
 
diff --git a/src/Symfony/Component/Process/Tests/AbstractProcessTest.php b/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
index 91b8aca20d..d5bb967972 100644
--- a/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
+++ b/src/Symfony/Component/Process/Tests/AbstractProcessTest.php
@@ -583,7 +583,14 @@ abstract class AbstractProcessTest extends \PHPUnit_Framework_TestCase
         }
         $duration = microtime(true) - $start;
 
-        $this->assertLessThan($timeout + Process::TIMEOUT_PRECISION, $duration);
+        if (defined('PHP_WINDOWS_VERSION_BUILD')) {
+            // Windows is a bit slower as it read file handles, then allow twice the precision
+            $maxDuration = $timeout + 2 * Process::TIMEOUT_PRECISION;
+        } else {
+            $maxDuration = $timeout + Process::TIMEOUT_PRECISION;
+        }
+
+        $this->assertLessThan($maxDuration, $duration);
     }
 
     public function testCheckTimeoutOnNonStartedProcess()