推 hankower : 最后是Win10不支援SMT？！
推 ayasesayuki : 应该是支援smt让效能更差
在此Reddit回文中往下找找到原Po的解释:
原因是Windows 7处理Ryzen SMT的执行绪才是对的
Win 10分不出Ryzen哪个是实体核心还是SMT,
就把两个执行绪在低执行绪负载时推给一个核心
而且Windows 10有没有把执行绪像群组指定般处理,
移动那些绪到其他的群组核心, 把快取给浪费掉了
故AMD说他们在微软一块写Win 10的更新档
所以现在Win 10用Ryzen要得关掉SMT
AMD said they are working with MS for a Win 10 update, but it's clear,
Ryzen with SMT off is faster than on in Win 10.
But Win 7 with SMT on is faster still. O_o
Win 7's scheduler actually handles Ryzen SMT threads correctly,
and this relates to Win 10 not knowing which Ryzen thread are physical or SMT,
shoving 2 threads into 1 core when under low thread workloads...
Also potential issues with Windows 10 not treating the threads as CCX
specific, moving them to the other CCX cores, trashing the cache. :/
This is a pretty serious perf hit,
these issues should have been fixed for launch. -_-