ZDNet: New Utlity to Overclock Mac Pro
Well, they claim you can OC a 2.8GHz mac pro to 3.2GHz safely using this utility.
I've downloaded the app and will post results as soon as I can.
One caveat -- no performance improvement in Xbench (or other benchmarks) but the article seems to address this and suggests a stop watch to see the real-world performance gains since the Mac clock is tied to the system clock.
From the article:
+Unlike Windows, Linux and many Hackintosh versions, Mac OS uses the bus clock speed as the time source. It is compared with real time when booting up. Nor does time correction by means of the Mac OS NTP daemon succeed: It simply no longer works with a large discrepancy between the bus clock and real time.+
+Whereas programmers of the IBM PC XT had to be forgiven for using the bus clock speed because of inadequacies of its Intel 8253 timer module, it should be reasonable to expect more from Apple, who now only offer computers with modern HPET timers. After all, multimedia applications use the HPET module. So videos do not run faster after overclocking.+
+The only option for "normalising" the time of the Mac Pro again is to restart without switching off the computer. ZDNet Clock is fundamentally "reboot-proof". But there are a few snags. The latest series of the Mac Pro (Mac Pro 3.1) can indeed be overclocked in the ZDNet test up to 3241 MHz while remaining stable. But a reboot without crashing is only possible up to 3178 MHz. Carefree overclocking fun does not exist beyond this frequency.+
Here is the article and download to the utility:
http://www.zdnet.de/enterprise/mac/hardware/0,39038647,39192217-1,00.htm
I've downloaded the app and will post results as soon as I can.
One caveat -- no performance improvement in Xbench (or other benchmarks) but the article seems to address this and suggests a stop watch to see the real-world performance gains since the Mac clock is tied to the system clock.
From the article:
+Unlike Windows, Linux and many Hackintosh versions, Mac OS uses the bus clock speed as the time source. It is compared with real time when booting up. Nor does time correction by means of the Mac OS NTP daemon succeed: It simply no longer works with a large discrepancy between the bus clock and real time.+
+Whereas programmers of the IBM PC XT had to be forgiven for using the bus clock speed because of inadequacies of its Intel 8253 timer module, it should be reasonable to expect more from Apple, who now only offer computers with modern HPET timers. After all, multimedia applications use the HPET module. So videos do not run faster after overclocking.+
+The only option for "normalising" the time of the Mac Pro again is to restart without switching off the computer. ZDNet Clock is fundamentally "reboot-proof". But there are a few snags. The latest series of the Mac Pro (Mac Pro 3.1) can indeed be overclocked in the ZDNet test up to 3241 MHz while remaining stable. But a reboot without crashing is only possible up to 3178 MHz. Carefree overclocking fun does not exist beyond this frequency.+
Here is the article and download to the utility:
http://www.zdnet.de/enterprise/mac/hardware/0,39038647,39192217-1,00.htm
Mac Pro 8-core 2.8GHz, Mac OS X (10.5.3)