We can separate power supply companies into three groups: the ones that design and manufacture their own products (the minority), the ones that design their own products but hire another company to manufacture the products for them, and the ones that use OEM products, i.e., another company designs and manufactures their products, but adding the label, box and manual from the contracting company. Almost all well-known manufacturers that aren’t originally from the power supply business fall in this last category.
Is this bad? Maybe. As the quality of the power supply will not depend on the labeled brand but on the real manufacturer, a given brand can provide a terrific product line on their original business (memory, cooling or whatever) but a different quality level for their power supply line. But we strongly believe that manufacturers will choose other manufacturers with the same quality level or they would get burned pretty quickly.
We can also have the funny situation of two different brands providing exactly the same power supply, as many original manufacturers are providing products to more than one brand. In some situations you can also find the same power supply on the market under the real manufacturer brand.
Here are two examples: XFX 750 W Black Edition is a relabeled Seasonic M12D 750 W, and SilverStone Element ST75EF is a relabeled Seventeam ST-750P-AF.
Everything will depend on the agreement between the two companies, as this agreement will say if the original manufacturer can or cannot sell their products to other companies or even sell them under their own brand. Sometimes they will agree that products picked to be manufactured under brand “X†will be exclusive, but other products can be sold to other companies. Sometimes the agreement will say that after “x†months the original manufacturer has the option to also sell the same product under their own brand or to sell it to other companies to be labeled under different brands.
Keep in mind that a company can buy power supplies from more than one source. If you find out that model ABC from brand MNO was manufactured by company XYZ, this does not necessary mean that all other models from MNO will also be from XYZ.