Hello,
just tested a clean SilverStripe 3.1.1 installation on PHP 5.4 and PHP 5.5 as my hosting company wants to updated to PHP 5.5.3 soon. The outcome is SilverStripe 3.1.1 doesn't run on PHP 5.5.x due to a fatal memory size error.
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 65488 bytes) in framework\core\Config.php on line 576
Fazit: When using SilverStripe 3.1.x series, stick with PHP 5.4 or lower and DON'T YET upgrade to PHP 5.5.
Cheers cwsoft