A/B Testing PC Power Supply Calculator Examples
Worked examples show how different PC build loads, reserves, and target PSU loads affect power supply estimates.
These examples use estimated high-load component wattages and show why the more demanding configuration determines the PSU rating when one unit may support either build.
Midrange Gaming Build vs GPU Upgrade
A 650 W PSU is evaluated against a 410 W current build and a 530 W upgraded build using a 20% reserve and 80% target load.
Input Summary
Current PSU
650 W
Build A base load
410 W
Build B base load
530 W
Reserve and target load
20% reserve, 80% target
Calculation Breakdown
- 1Build A reserved load410 * 1.20492 W
- 2Build B reserved load530 * 1.20636 W
- 3Build B recommended ratingceil((636 / 0.80) / 10) * 10800 W
Result Summary
Build B recommended rating
800 W
A/B Testing PC Power Supply Calculator
Build A is estimated at 75.7% of the 650 W PSU, while Build B is estimated at 97.8%. The shared estimated recommendation is 800 W.
Compact PC With Low-Power Graphics
Build A uses integrated graphics, while Build B adds a 180 W graphics card. A 15% reserve and 85% target load are used.
Input Summary
Current PSU
550 W
Build A base load
190 W
Build B base load
350 W
Reserve and target load
15% reserve, 85% target
Calculation Breakdown
- 1Build A reserved load190 * 1.15218.5 W
- 2Build B reserved load350 * 1.15402.5 W
- 3Build B recommended ratingceil((402.5 / 0.85) / 10) * 10480 W
Result Summary
Build B recommended rating
480 W
A/B Testing PC Power Supply Calculator
The 550 W PSU is estimated to run at about 39.7% for Build A and 73.2% for Build B after reserve.
High-Load Workstation Alternatives
Both builds use a 1000 W PSU. Build B has a higher-power GPU and more accessory load. A 25% reserve and 80% target load are used.
Input Summary
Current PSU
1000 W
Build A base load
720 W
Build B base load
820 W
Reserve and target load
25% reserve, 80% target
Calculation Breakdown
- 1Build A reserved load720 * 1.25900 W
- 2Build B reserved load820 * 1.251025 W
- 3Build B recommended ratingceil((1025 / 0.80) / 10) * 101290 W
Result Summary
Build B recommended rating
1290 W
A/B Testing PC Power Supply Calculator
Build A is estimated at 90.0% of the 1000 W PSU, while Build B is estimated at 102.5%. The shared recommendation is 1290 W.
How to Read Your Results
Reserved peak load is the component total after applying the selected transient reserve.
PSU load percentage compares reserved load with the entered continuous PSU rating.
A negative spare-capacity result means the reserved estimate is above the entered PSU rating.
The recommended rating is rounded up to the next 10 W and is based on the more demanding build.
Use the result as an estimate and separately check required connectors and PSU suitability.
Assumptions & Important Notes
- Examples assume component wattages can occur together under demanding workloads.
- The entered PSU ratings are assumed to be continuous output ratings.
- Reserve percentages and target load percentages are user-selected planning settings.
Related Examples
Frequently Asked Questions
Can two builds use the same PSU recommendation?
Yes. The calculator uses the larger recommended rating so one PSU estimate can cover either build.
Why do examples use a reserve percentage?
The reserve creates additional planning room for short spikes beyond the entered component estimates.
Should I use gaming power or stress-test power inputs?
Use estimates that reflect the demanding workloads you expect to run. A synthetic stress test may not represent typical use.
Ready to calculate your own result?
Use the live calculator with your own inputs, timing, and preferences.