Going Deep With SenseMI, XFR & More
Other than the antiquated manufacturing process being used for their production, current generation AMD processors havenít benefitted in any way from the advancements being rolled into successive APU generations. Remember, todayís highest-end CPU the FX-9590 uses a Piledriver microarchitecture that was introduced nearly a half decade ago. Meanwhile both Steamroller and Excavator have been launched without any paralleling updates within the FX-series.
As you can imagine this has all led to Zen incorporating countless improvements in the power efficiency front. Actually I misspoke; AMD isnít actually trying to make their next generation processors consume less power. Rather itís all about allowing them to achieve maximum performance while minimizing power.
In order to achieve these goals the aforementioned adaptive power and clock gating technologies have been combined under three primary terms under the SenseMI umbrella: Pure Power, Precision Boost and XFR.
In order to achieve these goals the aforementioned adaptive power and clock gating technologies have been combined under three umbrella terms: Pure Power, Precision Boost and XFR.
Very much like the older AMD initiatives like PowerTune and Enduro, Pure Power monitors core operations in real time with hundreds of sensors which log temperature, speed and voltage. It then optimizes the silicon responsiveness to enhance efficiency across all P-States while also allowing the chips to hit their idle rates much faster.
While the Pure Power algorithm adaptively manages and logs various core functions it works hand in hand with Precision Boost to maximize operational frequencies. The ďprecisionĒ part of this equation is due to the Boost algorithmís ability to accomplish extremely fine-grain 25MHz clock speed adjustments in an effort to squeeze every last ounce of attainable performance out of the silicon. In addition, each core can be clocked (or parked) individually depending upon the situation.
Those minute 25MHz increments work in parallel with the aforementioned sensors that pull data from the core every millisecond. Voltage can also be adjusted on the fly at 0.6mV for even more granularity. The end result is a CPU design that can respond extremely quickly to changing workloads and whose frequency over time looks more like that of a modern GPU. Indeed, we can see how AMD is leveraging their education in the GPU world to make more efficient x86 processors.
By this point it should be obvious that every Zen-based processor will feature an effective frequency range denoted by a Base and Precision Boost clock. However, AMD didnít stop there and have implemented something of an ode to enthusiasts with XFR. This so-called Extended Frequency Range is supposed to scale clock speeds depending upon core temperatures and thus will reward cooler running systems with a single thread clock speed that could extend above the chipís stated maximum Precision Boost limit. This is a very important distinction to make: XFR is only meant for single thread workloads.
XFR is included on all Ryzen processors, but to different extents. Processors with the "X" designation can extend their Boost frequency by 100MHz while all other non-X parts could see up to a 50MHz increase under the right conditions.
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