Last week, we published our AMD 2nd Gen Ryzen Deep Dive, covering our testing and analysis of the latest generation of processors to come out from AMD. Highlights of the new products included better cache latencies, faster memory support, an increase in IPC, an overall performance gain over the first generation products, new power management methods for turbo frequencies, and very competitive pricing.

In our review, we had a change in some of the testing. The big differences in our testing for this review was two-fold: the jump from Windows 10 Pro RS2 to Windows 10 Pro RS3, and the inclusion of the Spectre and Meltdown patches to mitigate the potential security issues. These patches are still being rolled out by motherboard manufacturers, with the latest platforms being first in that queue. For our review, we tested the new processors with the latest OS updates and microcode updates, as well as re-testing the Intel Coffee Lake processors as well. Due to time restrictions, the older Ryzen 1000-series results were used.

Due to the tight deadline of our testing and results, we pushed both our CPU and gaming tests live without as much formal analysis as we typically like to do. All the parts were competitive, however it quickly became clear that some of our results were not aligned with those from other media. Initially we were under the impression that this was as a result of the Spectre and Meltdown (or Smeltdown) updates, as we were one of the few media outlets to go back and perform retesting under the new standard.

Nonetheless, we decided to take an extensive internal audit of our testing to ensure that our results were accurate and completely reproducible. Or, failing that, understanding why our results differed. No stone was left un-turned: hardware, software, firmware, tweaks, and code. As a result of that process we believe we have found the reason for our testing being so different from the results of others, and interestingly it opened a sizable can of worms we were not expecting.


An extract from our Power testing script

What our testing identified is that the source of the issue is actually down to timers. Windows uses timers for many things, such as synchronization or ensuring linearity, and there are sets of software relating to monitoring and overclocking that require the timer with the most granularity - specifically they often require the High Precision Event Timer (HPET). HPET is very important, especially when it comes to determining if 'one second' of PC time is the equivalent to 'one second' of real-world time - the way that Windows 8 and Windows 10 implements their timing strategy, compared to Windows 7, means that in rare circumstances the system time can be liable to clock shift over time. This is often highly dependent on how the motherboard manufacturer implements certain settings. HPET is a motherboard-level timer that, as the name implies, offers a very high level of timer precision beyond what other PC timers can provide, and can mitigate this issue. This timer has been shipping in PCs for over a decade, and under normal circumstances it should not be anything but a boon to Windows.

However, it sadly appears that reality diverges from theory – sometimes extensively so – and that our CPU benchmarks for the Ryzen 2000-series review were caught in the middle. Instead of being a benefit to testing, what our investigation found is that when HPET is forced as the sole system timer, it can  sometimes a hindrance to system performance, particularly gaming performance. Worse, because HPET is implemented differently on different platforms, the actual impact of enabling it isn't even consistent across vendors. Meaning that the effects of using HPET can vary from system to system, as well as the implementation.

And that brings us to the state HPET, our Ryzen 2000-series review, and CPU benchmarking in general. As we'll cover in the next few pages, HPET plays a very necessary and often very beneficial role in system timer accuracy; a role important enough that it's not desirable to completely disable HPET – and indeed in many systems this isn't even possible – all the while certain classes of software such as overclocking & monitoring software may even require it. However for a few different reasons it can also be a drain on system performance, and as a result HPET shouldn't always be used. So let's dive into the subject of hardware timers, precision, Smeltdown, and how it all came together to make a perfect storm of volatility for our Ryzen 2000-series review.

A Timely Re-Discovery
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  • mapesdhs - Sunday, May 06, 2018 - link

    Indeed, all of this could explain why I had some weird results a couple of years ago when testing certain setups with a 980 Ti, I think one of the oc tools may have forced HPET in the manner described. I need to check. To be precise, with hindsight it correlates with the time MSI changed Afterburner to make use of RivaTuner. I could be wrong, but just maybe RivaTuner forces HPET as the main timer... Reply
  • HStewart - Wednesday, April 25, 2018 - link

    Did you hear the news of "Chris Hook" senior Marketting director at AMD leaving. It possible that the effect of Raju leaving AMD has much more effect then people realize.

    It good to see competition out there, it helps the industry stay a live - but I concern that at least for AMD that it will be a short fused.
    Reply
  • Hifihedgehog - Wednesday, April 25, 2018 - link

    Chris Hook was not very tech savvy for someone of his position so I am relieved he has left. He started working at ATi around 2000, yet he claimed in his farewell letter that high resolution gaming at the time constituted 320x240. We are all fortunate that the company has shed his weight and his position is now in far more competent hands. Reply
  • HStewart - Wednesday, April 25, 2018 - link

    It is interesting that people say so much good things about people while they were working there but when they leave they make them sound like traitors - but I see it differently - for someone to be there so long and such a high position - they maybe seeing writing on the wall.

    Big question is where did Chris Hook go - and yes back in early days we did not have 4k or even 1080P. I actually talk to ATI developers during latte 1990's and early 2000. Back then GPU's were stupid

    Keep in mind this guy was Marketing, not technical

    But to me this is sign that AMD is burning the candle at both ends if you combine it with Raju
    Reply
  • oleyska - Wednesday, April 25, 2018 - link

    Have you seen ALL the big players that was with AMD and ATI when they were really good?
    They are rejoining, it's a writing on the wall.
    AMD is a good company to work for again, those who worked there a decade ago was really passionate about their work and company then Hector Ruiz came and it ended with bulldozer, selling off glofo, overpaying for ATI and left when nothing was in any way positive apart from an GPU hardware product stack that was good.
    Reply
  • Hifihedgehog - Wednesday, April 25, 2018 - link

    This as well. Reply
  • Hifihedgehog - Wednesday, April 25, 2018 - link

    This is an exaggeration when, in reality, it is strictly a case by case basis that such judgement calls should wisely to be made. For example, when Steve Ballmer left Microsoft, it was a positive thing overall for the entire company to be shed of his weight. Usually, these “writing on the wall” conclusions are prematurely drawn by news venues who are desiring to make a hot, trending news item that are not necessarily accurate or fact-based. As to here, in truth, I never held Chris Hook or Raju Koduri in high regard, before, during or after their announced exoduses from AMD—both came across as underqualified and unknowledgeable for their respective management levels. Reply
  • Manch - Wednesday, May 02, 2018 - link

    HStewart is a Intel fan boy. Despite the turnaround for AMD in the CPU space, according to HStewart the sky is always falling for AMD. Intel can do no wrong. Reply
  • Death666Angel - Monday, April 30, 2018 - link

    "and yes back in early days we did not have 4k or even 1080P."
    Yeah, but my first PC when I was 12 years old in 2000 had a mediocre monitor with a 800 x 600 resolution (friends had 1024 and a bit later 1280). Him saying that in 2001, when he joined, 320 x 240 was high res just seems ignorant. Or a crappy joke.
    Reply
  • arashi - Monday, July 02, 2018 - link

    HStewart displays the mental agility of a drunken cricket unless it is to defend Intel. Don't bother. Reply

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