The big gain in building your own rig is not how much you save the first time, it is when you are willing to spend a little more and get yourself something that will be much nicer and easily upgradable for way less in the future. For instance how many of you would pay $100 extra for a nicer case on a OEM computer? But if you invest that in a build your own computer you get to keep that case through many builds. The same goes for the PSU, add on bay devices etc... I bought thermaltake iboxes like a decade ago and still have them in all my PCs. With an OEM device you never know what might happen. I had a friend with an HP and he bought a GPU to add to it so he could game. He had the weirdest lag in the thing, it would depend on what way his player was facing. We could never figure out anything the only thing we could do was get rid of that HP. That same GPU worked fine in a custom built machine.