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Intel i7 busratio Guide


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#1
BountyX

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Edit: This issue seems to mostly effect Intel PM55 chipsets

I'm seeing many comments stating that i7 users must use "cpus=1 busratio=20" for installation and boot up of OSX. Then, people are getting reboot issues when they remove these boot options even after patching DSDT (which isn't necessary if you're on Voodoo 9.7). Well, if your getting reboot issues after an install and you have removed all your boot options, then busratio is mandatory for you to specify.

Remember the i7 has no front side bus, so how can we calculate the bus ratio? We don't, we just use the clock multiplier :thumbsup_anim: That is probably why OSX is forcing us to provide it.

Thanks to wikipedia, we have these values in a nice table. Just look at the MULT column for your i7 type (may need to scroll up) List of i7 Multipliers

So, for example, to boot an i7-720QM with all 8 cores active under Voodoo 9.7 (if you're running into reboot issues) your boot options would be "busratio=12". You may optionally specify "cpus=8" in addition to busratio.

To make this permanent, you have to edit a string file in com.apple.Boot.plist . To edit open up a terminal and type:
sudo pico /Library/Preferences/SystemConfiguration/com.apple.Boot.plist

and find the following string:

<key>Kernel Flags</key> 
<string></string>

Change to (change busratio value to match your i7 version):

<key>Kernel Flags</key> 
<string>busratio=12</string>

Your i7 rig should boot without reboot issues and all 8 cores active (yay!). Some people purposely set the busratio higher, although I'm not sure it would provide any performance gains at the OS level.

#2
RANDUMBNAME

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hI THANX FOR YOUR INFO AND EFFORT.

i HAVE THE EXACT CHIPSET YOU ARE TALKING ABOUT AND I FOLLOWED ALL INSTRUCTIONS,

TO INSTALL I DENEB 1.6 ON AN HP DV7-3085DX

EVERYTHING IS RUNNING BUT I ONLY SEE 1 CPU AND NEED TO LAUNCH WITH CPUS=1 BUSRATIO=20

wHEN I BOOT USING BUSRATIO=12 CPUS=8 I GET APIC ERROR..

aLSO I CANNOT FIND APIC IN BIOS THERE IS NO OPTION (INSYDEH20 BIOS)

I KNOW OTHERS HAVE GOTTEN ALL CORES WORKING.. CAN YOU PLS TELL ME WHAT IM DOING WRONG?



THANK YOU AND THANX TO BOUNTY X FOR DIRECTING ME HERE

#3
BountyX

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No need to shout =P . Try just busratio=12, without cpus. Also does your bios have any settings available for hypthreading?

#4
anthony boone

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New to the scene, how to get voodoo kernel? Just need a few pointers and I can find it.

#5
BountyX

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New to the scene, how to get voodoo kernel? Just need a few pointers and I can find it.

It's bundled with a package called iAtkos (you probably want version 7). The actually kernel itself is hosted at http://code.google.com/p/xnu-dev/

#6
taunt

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So there's no way aka patch to get it to see your processor without the busratio= flag? I have a AMD Phenom II X4 955 BE, and can't boot unless I use the busratio flag or I'll get a RTC KP.

#7
Sina

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Hi,


I tried to install OSX86 on my HP laptop, I'd previously installed iAtkos 7 on my desktop easily but the thing is I can't install none of the distros on my laptop !!
I tried iAtkos 7i & 5i & Snow Leopard but none of them worked !
the thing is I can get the installation done with options like cpus=1 and busratio=10.5 or 20 but I can't boot up the OS in anyway with any flags !!
and I'm pretty sure that the problem is with my mobo or cpu (mostly cpu) .
my laptop spec. are as below :

============================================
HP Pavilion DV6t-2000 series
Mobo : Intel (I'm guessing ... :confused: )
CPU : Intel Core i7 Q720 1.6 GHz 4 cores, 8 logical cores
RAM : 4 GB DDR3 (1333 hz bus)
Bios : Insyde F.13
H.D.D 500 GB SATA with Intel 5 series/3400 series 6 port SATA AHCI Controller
Audio : IDT HD Audio controller
VGA : Geforce GT 230 M (1 GB dedicated memory)
Network Card : Realtek RTL8168D/8111D
Wifi : Broadcom 802.11g
============================================


I tried different distros and they been installed successfully but none of them would boot even with many different setup combinations !

If you could help or point me in the right direction It'd be really really kind of you ! :(


Any help or info is greatly appreciated !


Thanks

#8
BountyX

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So there's no way aka patch to get it to see your processor without the busratio= flag? I have a AMD Phenom II X4 955 BE, and can't boot unless I use the busratio flag or I'll get a RTC KP.

You can modify com.apple.Boot.plist in Extras folder to make it a permanant patch. Search around for modding that file for more detailed instructions.




Hi,


I tried to install OSX86 on my HP laptop, I'd previously installed iAtkos 7 on my desktop easily but the thing is I can't install none of the distros on my laptop !!
I tried iAtkos 7i & 5i & Snow Leopard but none of them worked !
the thing is I can get the installation done with options like cpus=1 and busratio=10.5 or 20 but I can't boot up the OS in anyway with any flags !!
and I'm pretty sure that the problem is with my mobo or cpu (mostly cpu) .
my laptop spec. are as below :

============================================
HP Pavilion DV6t-2000 series
Mobo : Intel (I'm guessing ... :confused: )
CPU : Intel Core i7 Q720 1.6 GHz 4 cores, 8 logical cores
RAM : 4 GB DDR3 (1333 hz bus)
Bios : Insyde F.13
H.D.D 500 GB SATA with Intel 5 series/3400 series 6 port SATA AHCI Controller
Audio : IDT HD Audio controller
VGA : Geforce GT 230 M (1 GB dedicated memory)
Network Card : Realtek RTL8168D/8111D
Wifi : Broadcom 802.11g
============================================


I tried different distros and they been installed successfully but none of them would boot even with many different setup combinations !

If you could help or point me in the right direction It'd be really really kind of you ! :wub:


Any help or info is greatly appreciated !


Thanks





What chipset is your mobo?

#9
Sina

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You can modify com.apple.Boot.plist in Extras folder to make it a permanant patch. Search around for modding that file for more detailed instructions.









What chipset is your mobo?



actually i finally could get iAtkos 7 to boot on my system, but had to modify boot with cpus=1 and busratio (=30) flags, otherwise I face restart loops on boot !
anyways, still have 1 core of cpu activated but i have totally 8 cores, any clue how to activate all ?
is there anyway to get the system to boot without any flags ?

#10
Zman21295

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I have noticed that some people are having a hard time with the Busratio=xx and determining the correct number. All CPU's are different, the bus ratio is determined by how fast the processor is. Learn how to calculate busratio here:
http://www.insanelym...howtopic=240542

#11
Uhud

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im getting this same problem, i managed the install it using busratio=12 then after installation i cant get it to start. i tried all bus ratios and cpus but still loops in restart.

i used hazard, not iatkos or any other 1





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