compute capability
**Compute capability** is the **GPU architecture version identifier that defines supported instructions, memory features, and performance behaviors** - it determines what low-level optimizations and precision modes are available to compiled CUDA kernels.
**What Is Compute capability?**
- **Definition**: SM version number used by CUDA toolchains to target architecture-specific features.
- **Feature Envelope**: Controls availability of tensor instructions, cache behavior, and precision formats.
- **Compilation Impact**: Binary generation and PTX compatibility depend on selected architecture targets.
- **Runtime Effect**: Different capabilities can change kernel performance characteristics significantly.
**Why Compute capability Matters**
- **Correctness**: Using unsupported instructions for a target architecture causes build or runtime failures.
- **Performance**: Architecture-tuned kernels can unlock major speedups over generic builds.
- **Portability Planning**: Multi-architecture deployments need deliberate build matrices and compatibility policy.
- **Feature Adoption**: New precision modes and acceleration paths arrive with newer compute capabilities.
- **Lifecycle Management**: Capability awareness guides hardware upgrade and software roadmap decisions.
**How It Is Used in Practice**
- **Build Targeting**: Compile with explicit architecture flags matching deployed GPU fleets.
- **Fallback Strategy**: Provide compatible kernels or binaries for older capabilities where required.
- **Regression Testing**: Validate performance and numerics across each supported compute capability tier.
Compute capability is **the hardware contract for CUDA software behavior** - architecture-aware builds are necessary to achieve both compatibility and peak GPU performance.