Are you using the default secondary storage VM? By default, the SSVM is created with only 256MB in CCP 3.x /512MB in CCP 4.x. I currently have created a extra large System offering that has 2GB of RAM that speeds up volume snapshots and ISO/Template uploads. YMMV.
As a gotcha, make sure that you use the ID # from the 'disk_offering' table in MySQL section in step 2. If you use the ID from the offering in the UI, the console won't load after a cloudstack-management restart.