diff --git a/Zend/tests/new_oom.phpt b/Zend/tests/new_oom.phpt
index 6d4ba3d760b4..8d36a83f101a 100644
--- a/Zend/tests/new_oom.phpt
+++ b/Zend/tests/new_oom.phpt
@@ -1,5 +1,5 @@
 --TEST--
-Test OOM on new of each class
+Test OOM on new of each instantiable class
 --SKIPIF--
 <?php
 if (getenv("USE_ZEND_ALLOC") === "0") die("skip requires zmm");
@@ -8,14 +8,102 @@ if (getenv("SKIP_SLOW_TESTS")) die('skip slow test');
 --FILE--
 <?php
 
+function getOomProcessCount(): int
+{
+    $processCount = PHP_OS_FAMILY === 'Windows'
+        ? getenv('NUMBER_OF_PROCESSORS')
+        : shell_exec('getconf _NPROCESSORS_ONLN 2>/dev/null');
+    if (!is_string($processCount)) {
+        return 1;
+    }
+
+    $processCount = trim($processCount);
+    if (preg_match('/^[1-9][0-9]*$/D', $processCount) !== 1) {
+        return 1;
+    }
+    return min((int) $processCount, 4);
+}
+
+function startOomTest(string $php, string $file, string $class): ?array
+{
+    $output = tmpfile();
+    if ($output === false) {
+        echo "Class $class failed\nUnable to create output file\n";
+        return null;
+    }
+
+    $process = proc_open(
+        [$php, '--no-php-ini', $file, $class],
+        [
+            0 => ['null'],
+            1 => $output,
+            2 => ['redirect', 1],
+        ],
+        $pipes,
+    );
+    if (!is_resource($process)) {
+        fclose($output);
+        echo "Class $class failed\nUnable to start process\n";
+        return null;
+    }
+
+    return [
+        'class' => $class,
+        'output' => $output,
+        'process' => $process,
+    ];
+}
+
+function finishOomTest(array $test): bool
+{
+    $status = proc_get_status($test['process']);
+    if ($status['running']) {
+        return false;
+    }
+
+    proc_close($test['process']);
+    rewind($test['output']);
+    $output = stream_get_contents($test['output']);
+    fclose($test['output']);
+
+    if ($status['signaled']) {
+        echo "Class {$test['class']} failed\n";
+        echo "Process terminated by signal {$status['termsig']}\n";
+    } elseif ($output && preg_match('(^\nFatal error: Allowed memory size of [0-9]+ bytes exhausted[^\r\n]* \(tried to allocate [0-9]+ bytes\) in [^\r\n]+ on line [0-9]+\nStack trace:\n(#[0-9]+ [^\r\n]+\n)+$)', $output) !== 1) {
+        echo "Class {$test['class']} failed\n";
+        echo $output, "\n";
+    }
+
+    return true;
+}
+
 $file = __DIR__ . '/new_oom.inc';
 $php = PHP_BINARY;
+$classes = array_filter(
+    get_declared_classes(),
+    static fn(string $class): bool => (new ReflectionClass($class))->isInstantiable(),
+);
+$tests = [];
+$processCount = getOomProcessCount();
 
-foreach (get_declared_classes() as $class) {
-    $output = shell_exec("$php --no-php-ini $file $class 2>&1");
-    if ($output && preg_match('(^\nFatal error: Allowed memory size of [0-9]+ bytes exhausted[^\r\n]* \(tried to allocate [0-9]+ bytes\) in [^\r\n]+ on line [0-9]+\nStack trace:\n(#[0-9]+ [^\r\n]+\n)+$)', $output) !== 1) {
-        echo "Class $class failed\n";
-        echo $output, "\n";
+while ($classes || $tests) {
+    while ($classes && count($tests) < $processCount) {
+        $class = array_shift($classes);
+        $test = startOomTest($php, $file, $class);
+        if ($test !== null) {
+            $tests[] = $test;
+        }
+    }
+
+    $testFinished = false;
+    foreach ($tests as $index => $test) {
+        if (finishOomTest($test)) {
+            unset($tests[$index]);
+            $testFinished = true;
+        }
+    }
+    if (!$testFinished) {
+        usleep(1000);
     }
 }