You’ve picked a CPU, a motherboard, a shiny new graphics card, and a power supply — and then the motherboard refuses to boot because the RAM is the wrong generation, the GPU is two centimeters too long for the case, or the PSU doesn’t have the cable the card needs. Ordering incompatible PC parts is one of the most common and most expensive mistakes a builder can make: it costs you return shipping, restocking fees, weeks of waiting, and sometimes a damaged component. This PC build compatibility checklist walks you through every critical match point — CPU, motherboard, RAM, GPU,…