Notice that even an RTX 4090 system rarely pulls 850W continuously. So why do people buy 1000W PSUs? Two reasons: efficiency sweet spot and transient spikes. Modern GPUs, especially from NVIDIA’s RTX 30-series and AMD’s RX 6000/7000 series, can draw 2–3x their rated TDP for milliseconds. A 300W GPU might spike to 600W for 1/100th of a second.
Modern PCs run almost everything off the 12V rail. A PSU that says “500W” but only delivers 300W on +12V is lying. Check the spec label — +12V should be close to the total wattage. computer power supply wattage
If your PSU is barely adequate, that spike can trip overcurrent protection, shutting down the PC mid-game. High-quality PSUs handle these spikes better than cheap ones, even at the same wattage. Notice that even an RTX 4090 system rarely