fio vs MemTest86

fio is a free storage I/O workload simulator for performance testing and reproducing bugs. Its job files can define multiple threads, processes and files, with sequential, random or mixed reads and writes using buffered, direct or raw I/O. Tune block and I/O size, I/O engine, queue depth, target files or devices, and job count. Documented engines include Linux io_uring and libaio, POSIX asynchronous I/O, and synchronous read/write options. Separate engines support HTTP GET and PUT requests to WebDAV or S3 endpoints and access to Ceph RADOS and RBD. Verification options can check written data after a workload, including repeated burn-in tests. Results are available in normal text, terse, JSON and JSON+ formats, plus bandwidth and latency logs; terse output is intended for scripts, tables or graphs. fio supports Linux, Solaris, AIX, HP-UX, macOS, NetBSD, OpenBSD, Windows, FreeBSD and DragonFly. The HTTP engine supports direct I/O only at depth 1, with scaling through multiple jobs.

MemTest86 is a bootable utility that checks computer RAM for faults using memory test algorithms and patterns. It runs from a USB drive without an installed operating system, although Windows, Linux, or an Intel-based Mac can be used to create that drive. Version 11.7 requires UEFI firmware and x86 or ARM64 hardware, and does not support Apple Silicon M-series Macs. Its listed coverage includes 14 algorithms, such as SIMD, Row Hammer, and DMA tests, and support for DDR2, DDR3, LPDDR4, LPDDR5(x), ECC, CDIMM, and CAMM2 memory. It can create customizable HTML reports and, on supported configurations, decode an error address to identify a failed DIMM or chip. The Free Edition supports up to 16 CPU cores; Pro supports up to 512 and adds automation and custom tests. Site Edition adds PXE-based LAN deployment and Management Console integration. The Free Edition costs nothing; Pro Download costs $116, paid once.