|You haven't supplied enough info about your "branded" system.|
Generally, branded systems are those from HP/Compaq, Dell, Gateway, etc. DE-branded systems are the exact same as branded, but all the brand name logos, stickers, nameplates, model numbers, etc have been removed & the HDD is *usually* blank. I'm not sure if that's what you meant by "unbranded" or not? Here's an example of "debranded":
It's generally best to build it yourself (if you can) or have one custom built for you. That way you have control over which components are used & you can pick & choose what best suites your needs.