I have a Mac Pro 2.66GHz (MacPro1.1). I do indeed suffer the problems not being able to reboot when changing the clock speeds, but I still did some testing with this tool.
I was surprised that I am able to clock this computer up to 3.20GHz while being incredibly stable and reporting no parity errors. I could even clock it up to 3.28GHz which is the max and there are no sudden kernel panics, just some parity errors on one of the memory modules I installed.
I have 6GB of RAM, with 2GB originally coming from Apple.
This looks promising and I look forward to future updates. Glad to see that the newer Mac Pro's have success even when rebooting.
I have the "Original" 8-Core Machine (MacPro 2.1) with 3.0GHz.
Runns fine till 374MHz (Bus Clock), 1.498 MHz (MB Clock) and 3.374 MHz (CPU Clock). But I'm not able to reboot at any speed but the original one
I use 4GB Apple RAM... an wondering if it could be possible to use the (new) 800MHz RAM as well...? Maybe this would solve the problem...? At least could give me a higher range to overclock my Bus Clock...!?
Does the new RAM work with my machine, or am I stuck with the 667MHz models...?
For example - my old G4 500 Dual uses 100MHz Bus Speed and works well with 133MHz RAM...
I have the same model as you (Quad 2.66, MacPro1,1), I read the notes on ZDNet and I'm curious about what this means "not being able to reboot" --
does it mean that once you overclock, the reboot command doesn't work? Or that it causes a crash?
Are you forced to do a hard shutdown each time (pressing and holding the power button)?
If one has to do a hard shutdown then I guess I can't use it. It will throw all my RAID 1 volumes out of sync.
http://www.hardmac.com/news/2008-06-30/#8515I would restart before using it in Safe Mode, to make sure everything is clean and as few startup and background processes run.
I didn't follow my own advice and ended up having to spend an hour with Disk Utility and Disk Warrior cleaning up my own mess
.... but, it did run, and I could inch it up ever so slightly, not enough and obviously not something I'll do again for awhile.
One of the main author of the well known website MacBidouille succeed to overclock until 3.7GHz ! (and it looks stable)
Christopher, thank you for this smartly-designed utility. But before I experiment anywhere near the edge for my 2.8 MHz 2008 Mac Pro, I would love to understand a couple of things:
(1) Over a warm Restart, or alternately a cold boot, how are the overclocking parameters retained (or not)? Is the kext in the temp directory the source? Do the parameters NOT survive a cold restart. Which leads to . . .
(2) If one goes a bit to far out on that limb and the Mac goes wonky, how does one safely reboot into the original speed settings? I.e. how does one recover instead of another reboot into a crash? Or do the parameters NOT survive a cold reboot?
Is that why the overclock.kext is in the private/temp/ directory? Does it get deleted on cold boot?
I guess a little more detail about the locations and inner workings of the utility's generated files would be nice to have and would increase my confidence.
Once you overclock and reboot, the power light will flash rapidly and will not start up. You have to hold to power button to manually shut off the computer. Once you do this, your computer will start up normally, but the clock speed is reset back to default settings, which is 2.66GHz for you and me.
Only the newer Mac Pro's which were released in early 2008 will be able to reboot, as of now. I saw some mention of the author of this program looking into a fix for our models?
I tested this interesting little utility earlier, but unfortunately my Mac won't go above 2.84GHz before it falls over. I have tried this 4 times and the second time it froze at just 2.828GHz. The other failures consisted of the screen greying from the top, and the machine informing me it would need to be restarted. The fourth attempt I increased the fan speed to 50% (extremely noisy in the very quiet environment I live in!), and it went to 2.842GHz before it just froze.
I was running the console throughout, and saw no warning of the impending failures.
I have 8 x 1GB RAM, so all 8 slots are filled, and the utility I run under widgets always shows significant temperature differences between the memory slots, not huge, about 20ºF. The memory consists of the 2 original Apple 1 GB sticks and 6 x 1GB from OWC.
If it's not clear, this is the Jan 2008 model MacPro3.1!
I'll try taking out the extra memory later today and retesting to see what happens
Message was edited by: TV Pete