The HP Omen Obelisk is HP’s most upgradable PC, but it needs at least one more fan and isn’t entirely customizable. Most pre-built gaming desktops come with a proprietary part or two (often the motherboard). But the HP Omen Obelisk ($899.99 / £999 to start, $2,378.99 as tested) is based entirely around standardized, user-replaceable components. And while it’s super easy to make simple replacements, cable management is a bit difficult. Still, the Nvidia GeForce RTX 2080 graphics card and Intel Core i7-8700 CPU make for a competent gaming machine and workhorse.