It's the opposite.

```php
<?php
$data = array(
	10,
	'aa',
	array(),
	array('123'),
);
	
$count = 10000;
$start = microtime(true);

for($i = 0; $i < $count; $i++) {
	foreach($data as $val) {
		$a = $val === array();
	}
}

printf("#1, done in %f\n", microtime(true) - $start);

$start = microtime(true);
for($i = 0; $i < $count; $i++) {
	foreach($data as $val) {
		$a = empty($val);
	}
}

printf("#2, done in %f\n", microtime(true) - $start);
```

Result:

```
#1, done in 0.018374
#2, done in 0.012684
```