You've got to reboot after an install, dude. Probably 2-3 times. So much mess gets cached up during the install that doesn't release. Your machine will actually start paging [swap] if you don't reboot it. Login/out won't do, it's got to restart.
There's a one-line mention of this in the installation readme. I saw a guy the other day that was pulling his hair out over this, it had gone on for a week. Reboot and **poof**
However, I'm a newbie on this forum and newbies are basically dumbazzes so your mileage will vary