The fundamental difference is that AMD respects exclusion domains even when speculating a thing intel is notorious for not doing. It's a fundamental difference. Intel: speculate without checking rights and crush afterward if a violation happened. Gains some points in benchmarks but makes side channel exploits very interesting. AMD: speculate only on allow if allowed. No need to crush afterward, no speculation violate security. Costs some points in benchmarks but make side channel exploits not very interesting.