Hey @davidnewton01,
First, you will need to ensure that your host supports what WordPress recommends (see https://wordpress.org/about/requirements/).
Regarding Cornerstone requirements, regretfully, we don’t have specifics but Cornerstone alone requires minimum resources as it was tested in a shared hosting environment by our development team and I personally did test also.
Also so note what @Rad said previously.
If you only will use X and Cornerstone and nothing else, 128mb would suffice. But increasing to 256 to 512 MB is generally recommended as you would also need a other plugins. If you increased the memory using this code:
define( 'WP_MEMORY_LIMIT', '256M' );
define( 'WP_MAX_MEMORY_LIMIT', '512M' );
and Cornerstone is still slow, it could be that your host does not allow increasing the memory and the code does not take effect. That is common in shared hosting environments. Please check with your host.
In addition to this, make sure your host is using SSD drives.
Thanks.