It is possible to check the total power usage of a computer, but many systems do not provide this information directly. Using a UPS can help monitor power input, but it won't show output from the power supply. The critical factor when adding components like fans is the distribution of amps on the 12V line, as most fans operate on this voltage. Generally, adding another fan is safe since they draw minimal power, typically around 10W. Newer power supplies may have multiple outputs, allowing for better management of power distribution. Additionally, some users find that removing the side panel of the case can improve cooling and reduce fan noise, although this can lead to increased dust accumulation. Overall, concerns about overloading a 430W PSU with an additional fan are largely unfounded.