AMD and Intel Have Different HPET Guidance

A standard modern machine, with a default BIOS and a fresh Windows operating system, will sit on the first situation in the table listed above: the BIOS has HPET enabled, however it is not explicitly forced in the operating system. If a user sets up their machine with no overclocking or monitoring software, which is the majority case, then this is the implementation you would expect for a desktop.

AMD

We reached out to AMD and Intel about their guidance on HPET, because in the past it has both been unclear as well as it has been changed. We also reached out to motherboard manufacturers for their input.

For those that remember the Ryzen 7 1000-series launch, about a year ago from now, one point that was lightly mentioned among the media was that in AMD’s press decks, it was recommended that for best performance, HPET should be disabled in the BIOS. Specifically it was stated that:

Make sure the system has Windows High Precision Event Timer (HPET) disabled. HPET can often be disabled in the BIOS. [T]his can improve performance by 5-8%.

The reasons at the time were unclear as to why, but it was a minor part in the big story of the Zen launch so it was not discussed in detail. However, by the Ryzen 5 1000-series launch, that suggestion was no longer part of the reviewer guide. By the time we hit the Ryzen-2000 series launched last week, the option to adjust HPET in the BIOS was not even in the motherboards we were testing. We cycled back to AMD about this, and they gave the following:

The short of it is that we resolved the issues that caused a performance difference between on/off. Now that there is no need to disable HPET, there is no need for a toggle [in the BIOS].

Interestingly enough, with our ASUS X470 motherboard, we did eventually find the setting for HPET – it was not in any of the drop down menus, but it could be found using their rather nice ‘search’ function. I probed ASUS about whether the option was enabled in the BIOS by default, given that these options were not immediately visible, and was told:

It's enabled and never disabled, since the OS will ignore it by default. But if you enable it, then the OS will use it – it’s always enabled, that way if its needed it is there, as there would be no point in pulling it otherwise.

So from an AMD/ASUS perspective, the BIOS is now going to always be enabled, and it needs to be forced in the OS to be used, however the previous guidance about disabling it in the BIOS has now gone, as AMD expects performance parity.

It is worth noting that AMD’s tool, Ryzen Master, requires a system restart when the user first loads it up. This is because Ryzen Master, the overclocking and monitoring tool, requires HPET to be forced in order to do what it needs to do. In fact, back at the Ryzen 7 launch in 2017, we were told:

AMD Ryzen Master’s accurate measurements present require HPET. Therefore it is important to disable HPET if you already installed and used Ryzen Master prior to game benchmarking.

Ultimately if any AMD user has Ryzen Master installed and has been run at any point, HPET is enabled, even if the software is not running or uninstalled. The only way to stop it being forced in the OS is with a command to chance the value in the BCD, as noted above.

For the Ryzen 2000-series launch last week, Ryzen Master still requires HPET to be enabled to run as intended. So with the new guidance that HPET should have minimal effect on benchmarks, the previous guidance no longer applies.

Ryzen Master is not the only piece of software that requires HPET to be forced in order to do what it needs to do. For any of our readers that have used overclocking software and tools before, or even monitoring tools such as fan speed adjusters – if those tools have requested a restart before being used properly, there is a good chance that in that reboot the command has been run to enable HPET. Unfortunately it is not easy to generate a list, as commands and methods may change from version to version, but it can apply to CPU and GPU overclocking.

Intel

The response we had from Intel was a little cryptic:

[The engineers recommend that] as far as benchmarking is concerned, it should not matter whether or not HPET is enabled or not. There may be some applications that may not function as advertised if HPET is disabled, so to be safe, keep it enabled, across all platforms. Whatever you decide, be consistent across platforms.

A cold reading of this reply would seem to suggest that Intel is recommended HPET to be forced and enabled, however my gut told me that Intel might have confused ‘on’ in the BIOS with ‘forced’ through the OS, and I have asked them to confirm.

Looking back at our coverage of Intel platforms overall, HPET has not been mentioned to any sizeable degree. I had two emails back in 2013 from a single motherboard manufacturer stating that disabling HPET in the BIOS can minimise DPC latency on their motherboard, however no comment was made about general performance. I cannot find anything explicitly from Intel though.

A Timely Re-Discovery Forcing HPET On, Plus Spectre and Meltdown Patches
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  • mapesdhs - Sunday, May 6, 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 2, 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 2, 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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