Boostgate: AMD’s Boost Clock Controversy

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Expectations and Inevitable Disappointment

As a result of the earlier Ryzen series CPU’s and almost a decade of consistent behavior from Intel CPU’s setting the tone for what’s expected, AMD’s Ryzen 3000 series being handled differently is a problem. This isn’t a technical problem perse, but how these CPU’s have been marketed definitely is. AMD’s current Ryzen 3000 series processors have boost clocks which have been vastly increased over its predecessors. This is something that people with a basic understanding of process node improvements may have expected, but those of us who knew a bit more found shocking. I expected AMD would re-invest its power savings and transistor budget into performance. AMD certainly did do that. We expected the Ryzen 3000 series to follow in the footsteps of the earlier CPU’s as it wasn’t an entirely new design. I had figured on a 100-200MHz clock speed increase. We were very surprised when AMD announced the boost clock frequencies were so high. 4.6GHz on a 12-core processor sounded too good to be true. As it turns out, this is in fact, the case.

The Ryzen 3000 series CPU’s have only one or two cores that can reach the advertised boost clocks or at least get close to them. The rest of the cores seem to be unable to do so. For those who don’t know, making CPU’s isn’t as exact a science as you would think. It’s not the same as building a simple machine like a firearm or a keyboard. CPU’s are incredibly complex and its closer to baking cookies than manufacturing as you might understand it. Each batch comes out a little different and individual CPU’s within that batch may come out better or worse. It’s like making chocolate chip cookies and seeing some cookies come out a bit softer, more browned, or containing less or more chocolate chips than other cookies in the same batch. Similarly, some CPU dies can achieve higher clock speeds than others, or, have slightly better thermal characteristics than others. Some dies even require less voltage to do the same thing as other dies.

Types of CPUs

AMD has two types of Ryzen 3000 series CPU’s. Some CPU’s contain a single core chiplet die or CCD and others that have two CCD’s. Within a given CCD, there are two CCX complexes containing the actual CPU cores. Even within a single CCX, you might have cores that clock better than others. These cores can all achieve the same minimum frequency, but unlike Intel, AMD does not guarantee these can all achieve the same maximum frequencies.

If you use the Ryzen Master utility from AMD, you can see the cores ranked. Cores with a gold star are the best on the CPU package, while others may be best within a certain CCD or CCX. Cores with a gold star, silver star, or silver dot are better than unmarked cores. AMD is pushing the boundaries of what this silicon can do, and as a result, not all chiplets are as good as the others. CPU’s with a single chiplet seem to be better behaved than dual chiplet CPU’s. The general consensus is that a CPU like the Ryzen 9 3900X has one “chiplet” and one “craplet”. The chiplet being the one that contains the core with the gold star that can achieve the maximum boost clock frequency. The craplet being the one that contains those cores that hold you back from achieving much at all.

AMD never guaranteed we would see maximum boost clocks on all the cores. In fact, the reviewer’s guide that every reviewer received showed a frequency ramping chart that showed the expected clocks of a Ryzen 9 3900X in a heavily threaded workload. This indicated that these CPU’s could likely only sustain roughly 4.15GHz using all 12 cores and 24 threads. With the IPC improvement over its predecessor and the core count increase, the Ryzen 9 3900X would become the most powerful mainstream CPU outside of gaming at the time of release. This combined with the fact that the CPU is priced at $499.99, meant it was an overnight sensation. Despite being relatively expensive for a mainstream processor, to this day Ryzen 9 3900X’s do not remain in stock anywhere for very long. At my local Microcenter, they can’t keep one for a full 24 hours before it’s sold.

Dan Dobrowolski
Dan has been writing motherboard reviews for the past 15 years, with the first decade or so writing for [H}ard|OCP. Dan brings his depth of knowledge about motherboards and their components to his reviews here at The FPS Review to help you select the best one for your needs.

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