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OS X Mavericks with Overclocks


shrieken213
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So I've been running Mavericks 10.9.1 via vanilla install on this build for a couple weeks now:

Gigabyte GA-Z87MX-D3H

Gigabyte GTX 770 4GB

i7-4770K

And for a while I never even needed boot flags to boot properly. Now I tried to overclock the CPU, and for a while OS X recognized this as well since HWMonitor was able to see both the increased Vcore and multiplier fine.

 

I dual boot with Windows, so I also have to stress test the overclock for stability. I found that 4.4Ghz was extremely unstable, so I raised the VRIN and VRING  to 1.9V and 1.155V respectively (~0.1V bump each), turned off all C-states and EIST. Now the computer can pass 12+ hours of prime95 blend.

 

But the problem is with OS X. Whenever I boot with this configuration, I get a kernel panic before anything can load: "Unable to find driver for this platform: "ACPI/"" or something of the like. Every time the source of the crash is com.driver.AppleACPIPlatform. I read that this might be a problem with DSDT, but right now I am running a DSDT-free installation so that can't be it. I tried booting with acpi=no/null/off/etc., -x, -f, etc. to no avail.

 

What is even more interesting is that now OS X cannot even handle ANY overclock; it will only boot in optimized defaults. Whereas before OS X could handle sizable bumps in multiplier and Vcore (47x and 1.36V), even a 1x bump or 0.01V increase now causes a kernel panic with the same aforementioned error.

 

I tried using the patched AppleACPIPlatform.kext by crunk, and that didn't help at all either.

 

Does anyone have any idea why this is happening?

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I just experimented with the multipliers. It seems I cannot boot to OS X when it is clocked beyond 4.4Ghz. I turned the multiplier down by 1 (4.3Ghz) and OS X boots fine.

What's even more interesting is that at 4.5Ghz, Chameleon fails to boot at all, giving a memory allocation error at address 0x320 and the "This is a non recoverable errorSystem HALTED!!!" message. This leads me to believe that perhaps it is not OS X but rather Chameleon that is not able to keep up with the high clocks.

Memory is currently clocked at 1600Mhz; I'll try boosting the memory frequency to see if it solves the allocation error.

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the problem is not with osx or chameleon, both will let you boot 4.40 ghz fine. My guess is the "Unable to find driver" / acpi related boot errors are due to wrong boot loader settings (GenerateC / PStates ), or non correct smbios definition.Also the most exciting new features in the Z87 / mavericks are based on energysaving, what i meant is oc'ing your 4770K is fine but no need to turn the energy saving features off imho

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  • 4 months later...

the problem is not with osx or chameleon, both will let you boot 4.40 ghz fine. My guess is the "Unable to find driver" / acpi related boot errors are due to wrong boot loader settings (GenerateC / PStates ), or non correct smbios definition.Also the most exciting new features in the Z87 / mavericks are based on energysaving, what i meant is oc'ing your 4770K is fine but no need to turn the energy saving features off imho

The issue was the C-state and P-state generators. Once those are disabled, the Hack was able to boot correctly, although the clock speed under "About This Mac" was capped at 4.3Ghz.

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