How Much Power Does Your Graphics Card Need?

Calculating Power Supply Performance

Ideally, you’re not going to get close to the absolute limit of the power supply under constant load; the optimal range lies between 65% and 85% load. If load goes over 85%, the temperature regulation fan will run at full speed and you have to live with the louder noise. The next table shows the areas where brand name power supplies are at ease; those who aim for this region won’t have problems with the increased current flow at start-up from having multiple hard drives.

Checklist:

1. Identify the graphics card and take note of the actual power consumption (in watts) under full load.

2. Identify the power consumption of the remaining components and add it.

3. Ideally, the area from 65% to 85% constant load determines the power supply class.

4. Maximum current level on the 12 V line is calculated and compared to the performance data from the power supply.

Formula: current (amps) = power (watts) / voltage (volts)

5. Check the required power connectors for the graphics card, and choose a matching power supply or allow for adapters.