AMD Precision Boost 2 and Wraith Prism Deep Dive

When AMD presented it new Precision Boost 2 technology, I have to think AMD undersold the feature in terms of what it was actually able to accomplish. The original Precision Boost on the 1st gen Ryzen processors was anemic at best. After seeing what Precision Boost 2 can accomplish, do we even need to try to overclock our new 2700X? Blasphemy!


System Setups and Configuration

With our system here today, none of the benchmarks that we used in the 2700X review are directly comparable. The day after the review was published, AMD pushed out new Ryzen chipset drivers, v18.10.0418. Also, the day after our review, ASUS pushed out a new EFI for the ROG Crosshairs VII Hero motherboard. This EFI is not yet released on the ASUS support page, however you can grab it here. This BIOS along with the new chipset driver did have a positive impact on performance, and that is why you cannot compare these results to our previous.

We have also again put the Intel Core i7-8700K benchmark scores as a baseline for those interested, however those are not what we are focusing on.

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Precision Boost 2 and XFR2

There are two settings in our Crosshairs VII EFI (BIOS) that are specific to Precision Boost2 and XFR2, and currently both are not clearly labeled, and we have asked ASUS to be a bit more transparent on these labels. Currently you will see "Core Performance Boost" and "Performance Enhancer."

Core Performance Boost = XFR2

Performance Enhancer = Precision Boost 2

CPB/XFR2 has three settings, Auto, Enabled, and Disabled. From what I can tell there is no difference between Auto and Enabled. Using these turns on XFR2. We have used Enabled and Disabled for our results here today.

Performance Enhancer is a bit more convoluted. There are settings for Auto, Default, Level 1, Level 2, Level 3 (OC), and Level 4 (OC). Levels 1 and 2 are using rules sets specified by AMD as to how Precision Boost 2 is supposed to work. Levels 3 and 4 are actually overclocked settings as noted. For our testing here, we have used Level 2 which is part of AMD's Precision Boost 2 specification. Quite frankly, we did not touch Level 1 as it is supposed to be a "lesser" BP2 setting in that Level 2 allows a slightly higher TDP value. Levels 3 and 4 are technically overclocking in that these profiles go above and beyond TDP and clock settings. Level 3 as you will see, requires even better cooling than what we have used here with our XSPC custom cooling loop.

More deep dive information is in this PDF that covers the Crosshairs VII.

We are using the DOCP 3400 profile for all of our benchmarks here today, so this is static across all our results. Timings are 16-16-16-36-1T at 1.3v vDimm.

Precision Boost 2 Clocks

Below we have clocks, voltages, amd temperature values that we observed while monitoring the system under 1 thread and 16 thread loads using Cinebench.

For our base cooling we have used the included AMD Wraith Prism cooler that is supplied with the 2700X. I will tell you right now that we have used our Prism air cooler in the best possible scenario possible for us, as we have used it outside the case and on an open test bench with a 72F/22C ambient temperature. In a hot case that is not well ventilated, I would expect performance to degrade. Our water cooling loop is from XSPC and consists of a RayStorm Pro waterblock, RX480 V3 Radiator, and D5 Photon Reservoir/Pump Combo V2.

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As noted, above are the observed clocks, temps, and core voltages we observed while the CPU is loaded with 1T or 16T workloads. I am not going to tell you this is exactly what is happening in every workload you may run as that can vary from workload to workload. This should give you a good overview however. Outside of turning XFR2 on or off and setting the PB2 level, we have touched no other settings in the Crosshairs VII's EFI. You can see above where we have had some failures, and it is quite possible that some voltage tweaking could possibly overcome these failures. Once we passed the AMD rule setting in Level 2 things get a bit less stable.

I have included the Level 3 for Prism and H2O cooling, and a bit of Level 4 PB2 for H2O above. These are outside of AMD's Precision Boost 2 rule specifications, and truly "overclocking."

Wraith Prism Eye Candy