SWE-bench's pre-built Docker images are x86_64-only, so every test runs through QEMU emulation on ARM64 hosts. I built native ARM64 container images and measured a 6.3x test runner speedup.
swe-bench-fast is a Go reimplementation of the SWE-bench eval harness. It auto-selects native ARM64 images for the 78% of instances that support it and falls back to Epoch x86 images via QEMU for the rest. One command, full benchmark, either architecture.
1,798 of 2,294 instances run natively on ARM64. The remaining 496 (scikit-learn, matplotlib, xarray) require x86 due to binary conda packages that aren't published for ARM.