How can I make my RTX 4070 and i7 build quieter under load?

Start by finding out which fans are actually getting loud. Motherboard BIOS settings generally control the CPU and case fans, not the graphics card fans. A monitoring or fan-control utility can let you see GPU temperatures and adjust the GPU curve separately. You may also find that the GPU is reacting to a brief temperature spike, so adding a delay or a less aggressive curve can prevent constant ramping.

The fans do not need to keep the components under 80°C at all times. Modern CPUs and GPUs are designed to operate at higher temperatures, so allowing roughly 90°C or a little more, within the manufacturer’s limits, can make the fan curve much quieter. Set reasonable temperature targets rather than forcing the fans to run near maximum whenever the temperature briefly rises.

Replacing the fans can help, especially if the existing ones are loud at higher speeds. Noctua models are very quiet but expensive; Arctic P12 or P12 Max fans are a cheaper alternative. More fans are not automatically better, though. The Lancool 216 already has decent airflow, so tuning the curves and reducing heat output should come before adding a bottom fan or extra GPU cooling.

Undervolting or setting a power limit on both the GPU and CPU is probably the biggest improvement. They will produce less heat, so every fan can run more slowly. A moderate limit usually costs very little performance; for example, a GPU can often use substantially less power with only a small performance reduction. Change one setting at a time and test stability and temperatures afterward.

A utility such as FanControl can coordinate the CPU, case, and GPU fan behavior and let you create separate profiles. For light video playback, a quiet low-speed profile may be enough, while compression can use a more aggressive curve. Make sure the case fans respond to both CPU and GPU temperature, since a GPU workload may not noticeably raise the CPU temperature.