Memory is set to 128MB by default without needing of any changes in wp-config.
Your domain will use less memory and will work faster if you install a cache plugin, as far as we know Hyper Cache is 100% compatible with it.
If you want to experiment with the memory, you can add in .htaccess the following:
php_value memory_limit 64M
(64MB is an example - you can set it to whatever you want to). Our configuration supports the full range of php value commands.
