[Perf] Windows/x86: 1 Improvement on 6/24/2026 4:31:52 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [46b72c7c81592b429e062bacebe8d39f17362333](https://github.com/dotnet/runtime/commit/46b72c7c81592b429e062bacebe8d39f17362333)
Compare | [ce71db3201f610d5a8cbf692cc3081f8784992fc](https://github.com/dotnet/runtime/commit/ce71db3201f610d5a8cbf692cc3081f8784992fc)
Diff | [Diff](https://github.com/dotnet/runtime/compare/46b72c7c81592b429e062bacebe8d39f17362333...ce71db3201f610d5a8cbf692cc3081f8784992fc)
Configs | CompilationMode:tiered, RunKind:micro

### Improvements in System.Memory.Span<Char>

Benchmark | Baseline | Test | Test/Base | Test Quality | Edge Detector | Baseline IR | Compare IR | IR Ratio
-- | -- | -- | -- | -- | -- | -- | -- | --
|

• [StartsWith - Duration of single invocation]()
• 📝 - [Benchmark Source]()
• [ADX - Test Multi Config Graph]()

![graph]()
[Test Report]()

### Repro
General Docs link: https://github.com/dotnet/performance/blob/main/docs/benchmarking-workflow-dotnet-runtime.md

```cmd
git clone https://github.com/dotnet/performance.git
py .\performance\scripts\benchmarks_ci.py -f net8.0 --filter 'System.Memory.Span*'
```

### System.Memory.Span<Char>.StartsWith(Size: 3000)

#### ETL Files

#### Histogram

#### JIT Disasms

### Docs

[Profiling workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/profiling-workflow-dotnet-runtime.md)
[Benchmarking workflow for dotnet/runtime repository](https://github.com/dotnet/performance/blob/master/docs/benchmarking-workflow-dotnet-runtime.md)

Start with the benchmark source at src/benchmarks/micro/libraries/System.Memory/Span.cs lines 71-72 and the linked System.Memory.Span.StartsWith report. Run the provided benchmarks_ci.py command, then compare the x86 Windows result with the baseline and test reports. Done means identifying and addressing the reported performance behavior with a verified benchmark result.

Written by the indexing model from the issue text.