A/B Testing GPU Performance (Annual) Formula
Learn how annual GPU electricity cost, benchmark performance change, and performance-per-watt change are calculated.
This calculator compares GPU B with GPU A using matched benchmark scores, typical workload power draw, annual operating time, and an electricity rate. It estimates the benchmark and efficiency differences alongside GPU-only annual electricity costs.
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Annual Electricity Cost Savings With GPU B
Where:
Subtract GPU B's typical wattage from GPU A's, convert the difference to kilowatts, multiply by annual hours, then multiply by the price per kWh. A positive result means GPU B is estimated to cost less to power.
Variables Explained
| Variable | What It Means | Unit |
|---|---|---|
| gpuAPower - GPU A power draw | Typical measured GPU A power draw during the compared workload. | watt |
| gpuBPower - GPU B power draw | Typical measured GPU B power draw during the same workload. | watt |
| hoursPerDay - Average GPU use per day | Average daily number of hours spent running the workload. | hours |
| daysPerYear - Active days per year | Number of days per year that the workload is expected to run. | days |
| electricityRate - Electricity rate | Price paid for one kilowatt-hour of electricity. | currency |
| gpuAPerformance - GPU A benchmark score | GPU A score from the matched benchmark and test conditions. | benchmark points |
| gpuBPerformance - GPU B benchmark score | GPU B score from the same benchmark and test conditions. | benchmark points |
Step-by-Step Calculation
Calculate annual operating hours
Daily workload time is multiplied by the number of active days to estimate total annual runtime.
annualHours = hoursPerDay * daysPerYear
Estimate GPU A annual energy use
Watts are converted to kilowatts and multiplied by annual hours to produce kWh.
gpuAEnergy = (gpuAPower / 1000) * annualHours
Estimate GPU B annual energy use
The same kWh calculation is applied to GPU B.
gpuBEnergy = (gpuBPower / 1000) * annualHours
Calculate annual electricity cost
Each GPU's estimated kWh use is multiplied by the entered cost per kWh.
gpuAAnnualCost = gpuAEnergy * electricityRate; gpuBAnnualCost = gpuBEnergy * electricityRate
Find annual cost savings
A positive value indicates that GPU B has the lower estimated GPU-only electricity cost.
annualCostSavings = gpuAAnnualCost - gpuBAnnualCost
Calculate benchmark performance change
GPU B's score difference is expressed as a percentage relative to GPU A.
performanceDifference = ((gpuBPerformance - gpuAPerformance) / gpuAPerformance) * 100
Calculate performance-per-watt change
This compares benchmark points per watt, using GPU A as the baseline.
performancePerWattDifference = (((gpuBPerformance / gpuBPower) - (gpuAPerformance / gpuAPower)) / (gpuAPerformance / gpuAPower)) * 100
Worked example: 20,000-point GPU A versus 26,000-point GPU B
Annual operating hours
8 * 250
2,000 hours
GPU A annual energy
(250 / 1000) * 2000
500 kWh
GPU B annual energy
(220 / 1000) * 2000
440 kWh
Annual electricity costs
500 * 0.16; 440 * 0.16
GPU A: $80.00; GPU B: $70.40
Annual savings with GPU B
80.00 - 70.40
$9.60 per year
Performance and efficiency change
((26000 - 20000) / 20000) * 100; (((26000 / 220) - (20000 / 250)) / (20000 / 250)) * 100
30.0% faster; 47.7% better performance per watt
Final Result
At 2,000 annual operating hours, GPU B is estimated to be 30.0% faster, 47.7% more efficient by benchmark points per watt, and $9.60 cheaper per year in GPU electricity costs.
Assumptions
- ✓Both benchmark scores use the same application, workload, preset, resolution, drivers, and test method.
- ✓Each GPU draws its entered typical workload power during every active hour.
- ✓The electricity rate and usage pattern remain constant for the year.
- ✓The estimate includes GPU power only, not whole-system consumption.
Limitations
- !A single benchmark may not represent every game, application, AI model, rendering task, or compute workload.
- !Actual power draw can change with workload, frame caps, clocks, cooling, driver versions, and system configuration.
- !The result excludes CPU, memory, storage, displays, fans, power-supply losses, and idle power.
- !Annual electricity savings alone do not account for purchase price or other ownership costs.
Common Mistakes to Avoid
Comparing scores from different benchmarks, presets, resolutions, or driver versions.
Entering a GPU's advertised board power instead of typical measured workload draw.
Using total PC wall power as if it were GPU-only power.
Entering cents per kWh as a whole number when the calculator expects currency units, such as 0.16 for $0.16 per kWh.
Treating a positive annual savings result as proof that GPU B is better for every workload.
Related Formulas
Frequently Asked Questions
How is GPU annual electricity cost calculated?
Typical GPU watts are divided by 1,000, multiplied by annual operating hours to get kWh, and then multiplied by the electricity rate.
What does a positive performance change mean?
It means GPU B has a higher benchmark score than GPU A under the matched test conditions.
What does performance per watt measure?
It divides benchmark score by power draw. A higher value means more measured benchmark performance for each watt used.
Why are benchmark scores required to use the same settings?
Different settings can change the score independently of the GPU, making the percentage comparison unreliable.
Does the formula include the rest of the computer?
No. It estimates the electricity cost associated with the entered GPU power draw only.
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