Is there a big difference between the Balanced and Best Performance power modes in Windows 10?

Short answer: on real benchmarks, the gap between Balanced and Best Performance is small — often just a few percent — and the bigger difference shows up in responsiveness and consistency rather than raw scores.

What actually changes:

• Balanced keeps the CPU's minimum clock state low and only ramps up when it detects a heavy enough workload, which is efficient but introduces a tiny delay before you get full speed. That gap rarely shows up as a lower benchmark score — instead you feel it as micro-stutters in games, weaker 1% lows, apps taking a beat longer to open, and a general sense the PC isn't as eager as it should be. 
• Best Performance removes that ramping delay, so the CPU is ready to go immediately. But average frame rates usually climb only a few percent when switching plans — anyone promising a night-and-day difference is overselling it. The real improvement is in consistency and responsiveness, not peak throughput

As far as I know, there is no much difference between the two models. Always connect the laptop to power adapter when necessary!

There is no universal percentage difference between Balanced and Best performance on Windows 10. The result depends on the processor, OEM firmware, cooling, battery state, and workload. Balanced still allows the CPU to increase speed when work requires it, while Best performance tells Windows to favor responsiveness and higher performance more aggressively. That can shorten battery life, raise temperature, and increase fan noise. On many brief office tasks the measured difference may be small; sustained compiling, rendering, or other CPU-heavy work can show more benefit, although thermal limits may erase it. Modern Standby does not standardize this gap. To test your model, run the same task three times in each mode with identical power source, battery level, background applications, and room temperature. Compare completion time, not just clock speed, and record battery drain and temperature. Use Balanced normally, and choose Best performance on AC power when the measured gain matters.

During testing, scores typically show a balance between speed and efficiency, with CPU performance fluctuating according to demand.