Space dose not take to much time to load. its just like a character…
if you enter code like below.
echo "<h2 class="ptitle">".$title."</h2>";
OR
<h2 class="ptitle"><?php echo $title; ?></h2>
There is no big difference in loads… and also space dose not matter.
the first one will take the whole string into php generate where as the second one will be take only the php part which will echo / return the string from variable…
and also if we have more opening and closing tags php. it may slow down a bit but not much.
eg having more than 1000 of open and closing tags 
Just shared my thoughts. i might be wrong. but i think it should not be 