[Perf] Windows/x86: 2 Regressions on 8/2/2026 11:04:49 PM +00:00

### Run Information

Name | Value
-- | --
Architecture | x86
OS | Windows 10.0.22631
Queue | ViperWindows
Baseline | [a2f953fe266dc72602436e77614a9e10f60a7128](https://github.com/dotnet/runtime/commit/a2f953fe266dc72602436e77614a9e10f60a7128)
Compare | [abcd6eb3137ac133ef7f73eae95e7928160386c9](https://github.com/dotnet/runtime/commit/abcd6eb3137ac133ef7f73eae95e7928160386c9)
Diff | [Diff](https://github.com/dotnet/runtime/compare/a2f953fe266dc72602436e77614a9e10f60a7128...abcd6eb3137ac133ef7f73eae95e7928160386c9)
Configs | CompilationMode:tiered, RunKind:micro

### Regressions in System.Tests.Perf_Random

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

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

| 2.45 μs | 2.71 μs | 1.11 | 0.02 | False | | |
|

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

| 2.45 μs | 2.71 μs | 1.11 | 0.01 | False | | |

![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.Tests.Perf_Random*'
```

### System.Tests.Perf_Random.NextBytes

#### ETL Files

#### Histogram

#### JIT Disasms

### System.Tests.Perf_Random.NextBytes_span

#### 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 definitions in src/benchmarks/micro/libraries/System.Runtime.Extensions/Perf.Random.cs at lines 43-44 and 56-57, then run the provided benchmarks_ci.py command for System.Tests.Perf_Random. Compare the baseline and test results using the linked regression report and runtime commit diff. Done means the x86 Windows regression is explained and the benchmark confirms it is resolved or correctly triaged.

Written by the indexing model from the issue text.