HPET Disabled or Enabled

Ayahuasca · 22 Sep 2014 at 23:07

When I was benching yesterday I decided to disabled HPET in the bios, today after work I went on BF4 and received a D3D error, then on FIFA 15, then again on D3, these were all after restarts after each crash. Remembered I'd disabled HPET and went back into the BIOS and enabled it again. No crashes since, anyone experienced anything similar? I found a post on battlelog forums saying enabling HPET fixes crashes for some users.

shankly1985 · 23 Sep 2014 at 00:58

I enabled it in bios and then force enabled in Windows. This reduces the DPC latency a lot.

Disco_P · 23 Sep 2014 at 01:29

I have always have HPET enabled. No reason to disable it.

shankly1985 said:
I enabled it in bios and then force enabled in Windows. This reduces the DPC latency a lot.

What is DPC latency and how to I force HPET in windows.

Ayahuasca · 23 Sep 2014 at 01:36

shankly1985 said:
I enabled it in bios and then force enabled in Windows. This reduces the DPC latency a lot.

Yeah I've done that as well using bcdedit /set useplatformclock true in command prompt?

shankly1985 · 23 Sep 2014 at 01:51

Disco_P said:
I have always have HPET enabled. No reason to disable it.

What is DPC latency and how to I force HPET in windows.

DPC "Deferred Procedure Calls" To tell you the truth I dont full understand its full use. But I will explain how I understand it.

DPC is part of the Windows OS and its used to read Kernel drivers, everything inside windows has a High, Med and Low Priority and then Real Time... Some Drivers can make your System gain high DPC and this will make Audio and Video stutter or perform bad.

HPET was designed "I think" to help with Real time audio and video, basically speed up how the system handles the communication between all the drivers.

You can check your DPC latency with Programs like LatencyMon and then use a program like WinTimerTester to see what clock speed your Windows is running at.

Ayahuasca said:
Yeah I've done that as well using bcdedit /set useplatformclock true in command prompt?

Yeah thats the setting you should be running at 14mhz

ashmanuk67 · 23 Sep 2014 at 08:28

Is this a good thing to try for BF4?

Dicehunter · 23 Sep 2014 at 08:34

How do you enable this on the Z97 chipset ? Can't see the setting anywhere in the bios.

EDIT

Used WinTimerTester before I put the command in and it said 3.somethingsomething MHz, Now after a reboot it says 14.31818 MHz, Still can't find the HPET option in the bios though unless it's auto ?

Frenzy · 23 Sep 2014 at 10:46

ashmanuk67 said:
Is this a good thing to try for BF4?

Should be a good thing as it should help with hitreg as it is more accurate that the other method. Should also help with stuttering if you experience any.

ashmanuk67 · 23 Sep 2014 at 10:50

Frenzy said:
Should be a good thing as it should help with hitreg as it is more accurate that the other method. Should also help with stuttering if you experience any.

Nice

thanks will look into this.

shankly1985 · 23 Sep 2014 at 11:02

Dicehunter said:
How do you enable this on the Z97 chipset ? Can't see the setting anywhere in the bios.

EDIT

Used WinTimerTester before I put the command in and it said 3.somethingsomething MHz, Now after a reboot it says 14.31818 MHz, Still can't find the HPET option in the bios though unless it's auto ?

I think Asus have this on by default and can't be switched on or off.

Ayahuasca · 23 Sep 2014 at 11:57

HPET in my ASUS Maximus V Gene bios is in the advanced tab under PCH configuration, as shown here:

shankly1985 · 23 Sep 2014 at 12:01

Ayahuasca said:
HPET in my ASUS Maximus V Gene bios is in the advanced tab under PCH configuration, as shown here:

snip

Just looked on my board and its also there. Thanks

ashmanuk67 · 23 Sep 2014 at 23:14

shankly1985 said:
I enabled it in bios and then force enabled in Windows. This reduces the DPC latency a lot.

i have done the complete opposite? i have disabled it in bios and in windows just to see the effect and even though i only play BF4 the difference is very noticeable and for the better my BF4 CPU/GPU graph is much flatter and the game just seems so much smoother.

How is this so?

shankly1985 · 23 Sep 2014 at 23:23

ashmanuk67 said:
i have done the complete opposite? i have disabled it in bios and in windows just to see the effect and even though i only play BF4 the difference is very noticeable and for the better my BF4 CPU/GPU graph is much flatter and the game just seems so much smoother.

How is this so?

Not sure

maybe I should also test this. Be nice to maybe run some benchmarks and see if anything shows up?

setter · 23 Sep 2014 at 23:39

ashmanuk67 said:
i have done the complete opposite? i have disabled it in bios and in windows just to see the effect and even though i only play BF4 the difference is very noticeable and for the better my BF4 CPU/GPU graph is much flatter and the game just seems so much smoother.

How is this so?

Might try this as my graph is bouncing around all over the shop. Much flatter if i cap the framerate or use adaptive vsync.

ashmanuk67 · 23 Sep 2014 at 23:39

Reading up on this and seems more turn it off as windows 7/8.1 has better event timers well something like that

would be good to see what you think with them both set to off.

shankly1985 · 24 Sep 2014 at 00:59

ashmanuk67 said:
Reading up on this and seems more turn it off as windows 7/8.1 has better event timers well something like that
would be good to see what you think with them both set to off.

I'll test tomorrow, I have always switched mine on and have bios on default witch also sets to on.

I think with it on in bios and then off in Windows it uses a different type of timer.

What I will do tomorrow is run maybe 3D mark with on and off as this tests more of a system then just a game benchmark. Or do you guys think a game bench will be enough?

When you say you performance graph is more flat do you also notice more frame rate?

Rofflay · 24 Sep 2014 at 03:26

As a anti-stutter purist this was one of the tweaks i looked into for L4D as i had strafe judder. I remember checking this a year or more ago with wintimer and i used both DPC and Latencymon on win 7. There are good arguements for HPET, But in reality i remember reading and experiencing the opposite.

People say HPET = More input lag and higher latency. And sure enough when i ran it i would idle at 40us in windows. I also thought i had more mouse lag although could be placebo because others mentioned it. When i took off HPET latency dropped to 7us in windows. There are things i obviously disable and look at to shrink my latency but HPET off was my biggest gain.

So i will look again under win 8 because Ayahuasca has tickled my OCD itch. Im without a GPU until mid Oct though so you will need to experiement with BF4, Frametime tools Latency mon and DPC latency checker. So four tools and we should see 8 results and a summary on the feel between both.

ashmanuk67 · 24 Sep 2014 at 07:50

My frame rate is caped so cannot confirm but overall responsiveness is defiantly better though there are still spikes in the BF4 graph but does not seem to have much or any impact in the feel of the game.

For what I have read on this any game that is CPU dependent should show the effect better.
So for me both Bios and in windows HPET is turned off so would be good so what you think shanks

I'm sure this is not a placebo affect I play BF4 so much lol you just know it feels different.

setter · 24 Sep 2014 at 07:56

I'll try this later, do you have to disable it in both bios and windows? Bf4 is probably my most played game too.