Actually, UnrealFrontend (like all Slate apps we have except for the editor) uses a simplified renderer that works just fine even on Intel HD 3000, so in theory you should be able to use it on an old, low end Mac that doesn’t meet system requirements for the editor/games. That said, building and packaging a game can be a lengthy process, especially if it has to do some texture compression and shader compilation, so a Quad-core CPU and a graphics card that’s not extremely slow is highly recommended to minimize the time you spend waiting.