AMD's Ryzen 3000 Boost Fix Works, But Often Hits Wrong Cores

[harlan4096]

We've discovered quite a few encouraging traits with AMD's new boost-fixing BIOS and the Ryzen 9 3900X processor that extend beyond 'just' the expected heightened frequencies, but we also found a weakness in the chips' inability to hit the rated maximum boost speeds on all cores (the chips come with a mix of faster and slower cores). That often results in our Ryzen 9 3900X boosting on inactive cores, thus providing no performance improvement in some workloads.

AMD's Ryzen 3000 series debuted to wide acclaim with up to 15% higher instruction per cycle (IPC) throughput borne of the Zen 2 microarchitecture paired with the 7nm process, leading to a new level of value for the mainstream desktop. It also had the most cores we've seen on a mainstream platform, with more to come in the form of the 16-core 32-thread Ryzen 9 3950X later this month.

Unfortunately AMD has been criticized due to some chips' inability to hit the rated boost frequencies, which eventually led the company to issue the new firmware we're testing today. AMD says the new firmware improves clock rates by 25 to 50MHz, along with other fine-grained improvements. After several preliminary tests with beta firmware, we've found that AMD's updates correct the small clock rate deficit that we've seen with a few of our single-die Ryzen 3000 models, like the Ryzen 7 3700X.

While the new firmware delivers smaller boosts than expected, especially in light of the up to 300 MHz shortfall reported with the Ryzen 9 3900X in a recent survey, AMD does say that it corrects a firmware bug that reduces performance in some scenarios. With our testing of the single-die models complete, we're now focusing on the improvements for the multi-die Ryzen 9 3900X, which seems to be most impacted by the frequency deficit. We'll also test some adjustments AMD made to idle power consumption and see how the new update impacts AMD's auto-overclocking Precision Boost Overdrive (PBO) feature, but most importantly, examine how the Windows scheduler is still causing AMD problems.
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