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Test results for AMD Ryzen
Author: Agner Date: 2017-05-06 09:41
Phenominal wrote:
Some reviewers has mentioned that disabling SMT in BIOS has improved some benchmarks. This could also impact instruction fetch. Any truth to these statements?
The benchmarks are probably using as many threads as possible. The cost of SMT is that all the threads run at half speed, and you get additional cache evictions and branch mispredictions. The processor core has no problem allocating all resources to a single thread when it is only running one thread.

I don't have physical access to the machine I have tested so I haven't been able to experiment with the BIOS setting, but I haven't had any reason to do so either.

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