Velero, your specs are fine, since you are upgrading your GPU.
Run your machine through this:
http://www.systemrequirementslab.com/cyri/
A 1 click web tool to scan your system for hardware and setup configurations, select Silent Hunter 5 from the dropdown and hit canyourunit, let it do its thing and it'll give you a result.
And what power supply are you running?
What Vendor said is a good measuring tool.