Another look at HPET High Precision Event Timer

Like Agent-101 said it can't be disabled, in windows its off/default command, when I forced HPET in windows8 it performed worse - it was crippling raw cpu performance.

 

it must not like you..


for me my system seems smoother and more stable fps in game



but then every system has different results.

mostly on how the bios handles hpet.

I read that it doesnt handle well on some

 

Well it seemed windows auto selected the best option, if I forced HPET on top it lost some raw perf., e.g. Resident Evil5 fixed cpu benchmark.


My old mobo x48 had a option in bios and it needed this windows HPET on top or it ran worse/not so smooth, but now it had higher latency.

 

I would keep it enabled in BIOS. Windows on it's own doesn't trustworthy (or at the very least consistent); but Linux will use HPET while booting, and then switch over to TSC if possible. If I heard right in the past, HPET from BIOS does more than provide timing (but I could be wrong), and it being enabled generally shouldn't cause an issue as long as the OS is smart enough to choose the best timing method.

If HPET doesn't exist while Linux is booting; it'll use ACPI timings (which if I understand right, is more legacy) until switching over to TSC. No idea what Windows does in this situation.

 

it will use the best method supported by the hardware or application. There is a hierarchy, I can't remember the exact order but I think invariant TSC is at the top.

 

But then why does the useplatformclock entry seem inconsistent on it's appearance?

I do a lot of Windows reinstalls, and on some installs I see the entry in bcdedit, other installs I don't. Same exact hardware and BIOS. Only things that may change for the most part driver-wise because of updates is my Ethernet driver (Realtek GBe) and Catalyst (GPU and Chipset). I do the same setup process as well (Windows Updates, drivers, software, tweaks).

I only tried figuring out what changed the presence of that setting once, and it appeared right after installing Catalyst (I think I did GPU and Chipset stuff in the same session) and rebooting. Was certain it was some part of Catalyst, but now I'm not too certain (back when 14.12 released, I didn't have the useplatformclock entry; updated to the HDMI Fix 14.12 driver, and the entry appeared; now I'm on Xtreme-G 14.12 and don't see the entry).

 

The most simple explanation is - Bigfoot lives in your computer.

 

Has anyone actually published benchmarks with HPET on / off in BIOS and using the bcedit switch on/off etc ?

Would be interesting to see a comprehensive series of tests, disk i/o, framerate, frame jitter, various other things.

I disabled HPET in my bios, and using bcdedit and my latency in Latencymon went down really low, and when I do get glitches from the nVidia driver changing it's core speed - the lags are less.

I've used PowerMizer to force the GPU into 'Medium' or whatever (not at home now so can't recall exact terms) and that seems to have helped.

My main emphasis is audio latency since I do large audio projects.

 

Hi just want to share this.

I have a Gigabyte Z97X-SOC Force w/ F6 BIOS (UEFI) and even though I do not have any toggle for HPET under the BIOS when I did the CMD command under Windows 8.1 Pro x64 and and I got this from 3.9Mhz to 14.3Mhz.

 

Excuse the dark theme, can't stand Windows's default theme, eyes highly sensitive to light.

 

best thing for when working with audio is also disable any energy settings and speedstep so the processor stays at constant speed. it been noted on DAW sites that the processors enegery settings effect latency with audio

https://www.steinberg.net/en/suppor...ails/kb_show/optimizing-windows-for-daws.html

 

Yep, have done that already and many other things, ta for the link though

 

SpeedStep (EIST) is really bad for OC stability and whatnot, but CPU Enhanced Halt (C1E or C1/C6) is perfectly fine and saves heaps of power.

Just saying.

 

14.3MHz is typical result for HPET.

 

Yeah I noticed when I disabled EIST I was getting better OCs, though some people don't have issues with EIST, I guess it's very dependant on motherboard sability and the chipset you're using. So far my i7 2600k is going well at 4.8ghz. Recently got a Corsair H110, hoping to reach 5ghz but not don't think I'll be that lucky ;-)

 

I decided to take another look at this since I got my 980 and in any given game it can actually significantly decrease or increase performance.

The main reason I tried at all was simply because even without any AA in Final Fantasy XIV ARR, the game chokes and cannot maintain 60FPS due to the CPU. (1st gen i7 @4Ghz). Enabling Occlusion Culling fixes some of the issues, and does seem to point to being maybe draw call related. Monitoring core performance whichever thread is selected for what I assume is handling draw calls, the thread will be pinned between 75-100% usage when the drops are occurring.

Enabling HPET doesn't make a huge difference in this case. But in others, like Sniper Elite, it drops GPU usage significantly. In the benchmark my score drops from ~174FPS to ~144FPS @ 1080p

I wonder if I was less CPU bottlenecked if the difference would be less significant.

 

Take a GCN Radeon and test the HPET influence with Mantle (Sniper Elite 3)

 

i doubt c1e or c1/06 works if speedstep is disable.

 

Just done some tests on my 660ti Sli + Windows 10 (valley report as Win8)
On my rig Hpet Off both in windows and Bios gives higher Avg-Low-High fps, and a better gpu score.
I'll do some extended testing to see effect on stuttering.

Spoiler

 

No EIST is fine now with newer cpus, if you have instability then its bad OC by default, usually too low cpuv.. For example by Haswell its actually C7 that could cause instability by very high OC (sudden mid-high load and jump from C7 to C0)


Btw C1E is kinda bad if you want to have fixed stable cpu freq. all the time, otherwise it will down clock to stock turbo.. C3 is ok and is usually active by balanced power plan if configured properly, C6 (old cpus), C7s is only by power saver plan, C0 by high performance plan.