New BIOS, Performance Re-Tested

Introduction

There has been a lot of talk concerning the fact that reviewers (such as myself) didn’t see the advertised boost clocks on our Ryzen 9 3900X review samples. AMD has chimed in on what’s going on so we thought we would provide an update to our recent Ryzen 9 3900X review and discuss what happened and what’s going on now. There are also some other issues that people have noticed once these CPU’s were installed in new or existing builds. The Ryzen 9 3900X BIOS issues have been posted all over the web. We thought we’d chime in on those issues with a new BIOS version from MSI and re-test CPU performance.

AMD Ryzen 9 3900X CPU presentation slide

Clock Speeds

The first thing we want to talk about are the clock speeds on these CPU’s. The issue is simple: Reviewers generally didn’t see the advertised 4.6GHz boost clocks on their Ryzen 9 3900X review samples. The issue is further compounded by the fact that people don’t fully understand how boost clocks work and what they should be seeing.

Indeed, our review sample did not achieve the advertised 4.6GHz boost clocks during our review, although they were generally close. We saw clocks between 4.3GHz and 4.4GHz during lightly threaded or single threaded applications. Keep in mind, you will never see 4.6GHz boost clocks across all the cores when doing anything that’s heavily multi-threaded. We will talk more about that shortly.

To understand what’s going on, we need to explain what boost clocks are, and how they work. AMD processors come with a specific base clock frequency that is essentially your minimal clock frequency so long as conditions required for the CPU to operate normally are present. This is what is known as “stock” clock speeds. This is generally what you should see on all of the CPU cores.

Normal conditions would include specific ambient temperature ranges and a motherboard that meets the CPU’s requirements to function at minimum specifications and so on. If you have your CPU installed in an air cooled machine in an environment that’s hostile with temperatures well in excess of standard operating guidelines, then your CPU will not likely operate at even its standard base speed. But installed in a normal home or office, you should be fine.