So I've been running Mavericks 10.9.1 via vanilla install on this build for a couple weeks now:
Gigabyte GTX 770 4GB
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?