Author Topic: Workaround for Intel core 2 duo variance  (Read 563 times)

Offline Noir

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Workaround for Intel core 2 duo variance
« on: June 04, 2009, 07:18:56 AM »
Hi,

You Core 2 Duo (laptops) users have probably noticed that when you run AH the variance often looks like that :



Resulting in intense warping and making the game unplayable. After investigation it appears that the cause is the Intel Speedstep feature that changes the CPU clock when its not fully busy even when the power scheme is set to max performance in windows. The feature can't be deactivated on most recent CPU's. If I'm not mistaken aces high doesn't use 100% of both cores at all times, making the core speed change while the game is launched, and thus the variance is going crazy.

After hours of googling on the suject I found a little home made program called cpubusifier that uses all unused CPU cycles with the lowest priority possible, making the cpu always busy and stuck at max speed wich was the intended effect. Higher priority programs still work good with the busifiers running. You have to run cpubusifier one time for each core and using imagecfg I changed the default core affinity of cpubusifier, making one executable assigned to cpu0 and the other to cpu1.

Running the busifiers the variance looks like that :



There is a small loss of performance but you shouldn't be warping or seeing people warping, making the game playable  :aok

WARNING Running cpubusifier will make your laptop CPUs run at full speed all the time and the cooling fans will run at full speed too, decreasing their life span. People should also wait for skuzzy's validation if he ever gives one. Use that workaround at your own risk and only if you know what you are doing, I can't be made responsible for any damage.


On the bright side I'm using that trick myself for hours now and had no problems.

Here is the link. http://mapage.noos.fr/rsm/busifier.zip

Unzip, Switch you laptop to max performance, run both executables that are in the zip, and you are good to launch AH2. reboot after playing.

Don't hesitate to give feedback.




« Last Edit: June 04, 2009, 07:24:14 AM by Noir »
now posting as SirNuke

Offline Skuzzy

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Re: Workaround for Intel core 2 duo variance
« Reply #1 on: June 04, 2009, 07:26:24 AM »
"Speedstep" is a software controlled option.  Most system BIOS's allow you to disable it.  However, it would not surprise me to see the larger OEM's not give you that option in the system BIOS.

Yes, it should be disabled if you want to do anything real time.
Roy "Skuzzy" Neese
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Offline Noir

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Re: Workaround for Intel core 2 duo variance
« Reply #2 on: June 04, 2009, 07:28:26 AM »
Yes I should've said that first, disable speedstep if you can.
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Offline Plazus

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Re: Workaround for Intel core 2 duo variance
« Reply #3 on: June 04, 2009, 09:15:27 AM »
Have there been any similar problems with the Core 2s on desktop computers?
Plazus
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Offline MrRiplEy[H]

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Re: Workaround for Intel core 2 duo variance
« Reply #4 on: June 04, 2009, 09:48:57 AM »
Have there been any similar problems with the Core 2s on desktop computers?

I use speedstep on both my C2D desktops and my variance is flat. The only thing that caused problems was Virtualbox virtual network driver that messed AH variance.
Definiteness of purpose is the starting point of all achievement. –W. Clement Stone

Offline Noir

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Re: Workaround for Intel core 2 duo variance
« Reply #5 on: June 04, 2009, 10:02:30 AM »
Have there been any similar problems with the Core 2s on desktop computers?

Never seen any.
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Offline BaldEagl

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Re: Workaround for Intel core 2 duo variance
« Reply #6 on: June 04, 2009, 10:17:01 AM »
I use Speedstep on my gaming desktop and don't experience any problems with it whatsoever and the machine is even overclocked.  It turns the multipier down from 8 to 6 (and the CPU core from 400 to 300) when the extra speed isn't needed.  As soon as the CPU use bumps above 0% it cranks the multi back up.
I edit a lot of my posts.  Get used to it.

Offline Skuzzy

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Re: Workaround for Intel core 2 duo variance
« Reply #7 on: June 04, 2009, 10:20:54 AM »
As it should.  Speedstep, in of itself, is not normally a problem, unless you are using a mobile CPU with Vista. Basically, they fight with each other.  I believe the issues have been corrected in Windows 7.

Vista should have never been installed on a laptop with the bugs it has with power management.
Roy "Skuzzy" Neese
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