We here at PCWorld, we encourage you to try building your own desktop computer. It’s fun! It’s economical! It’s only very slightly likely to lead to your destroying fragile parts worth hundreds of dollars! All joking aside, sometimes buying a pre-built computer just makes sense. But what’s the difference between a PC sold by an OEM and one sold by an SI? We asked an expert, YouTube build master Braethorn, to break it down for us in the latest PCWorld video. First, let’s define some terms. OEM stands for “original equipment manufacturer,” and in the PC market it refers to companies like Dell, L…