Hardware researcher spins up 'CPU deoptimization' project to find the slowest single x86 instruction, creates hall of shame — worst offender takes 198 billion cycles spanning 62 seconds to execute
- ID
- 12211
- Status
- summarized
- Published
- 08 Aug 2026, 7:20 PM
- Fetched
- 08 Aug 2026, 8:10 PM
- Provider
- Tom's Hardware
- Category
- technology
- Original URL
- https://www.tomshardware.com/pc-components/cpus/hardware-researcher-spins-up-cpu-deoptimization-project-to-find-the-slowest-machine-code-worst-offender-takes-198-billion-cycles-to-execute
- Source URL
- https://www.tomshardware.com/feeds/all
Summary
- Score
- 3.0
- Created
- 08 Aug 2026, 8:10 PM
- Tags
- Audience
- developers
What happened
A hardware researcher built a 'CPU deoptimization' project to identify the slowest single x86 instructions, creating a 'hall of shame.' The worst offender takes 198 billion cycles—62 seconds—to execute a single instruction.
Why it matters
This is a curiosity rather than actionable guidance. Developers writing performance-critical x86 code or JIT compilers may find it interesting that certain instructions can stall a core for over a minute, but the article body is inaccessible (mostly site boilerplate), so specific instructions, mitigations, and CPU models cannot be extracted. No practical decision can be made from this text alone.
Discussion angle
Whether pathological instruction latency matters for real-world workloads or is purely an academic edge case—and whether anyone shipping JIT compilers or sandboxed execution should care about instruction-level timing attacks or stalls.