If anyone who knows about the technical side of the Mac Pro's motherboard could comment on the possibility of overclocking said beast, please share the wealth. cheers.

(I'd be interested in turning 2.66 into 3.0)

Maybe is posible but you have to change FSB from 333 to 375.
I don`t have any idea how you do that.....

No, not without getting crazy. However, the board is socketed so you can upgrade later.

Furthermore, there are no Xeon 771-Socket overclocking motherboards available yet either:

http://forums.2cpu.com/showthread.php?t=77365

I don't see it happening unless you know the motherboard can change memory/cpu voltage, be able to change the multiplier and/or fsb, or the cpu is unlocked. Current software overclocking applications wont help even under windows because these applications do not currently support these boards and will not support these boards unless there is an overwhelming demand for it.

I image some groups would end up hard-wiring the board or the chips when they get cheaper. But I don't think this will happen in the next 8-12 months.

hi, I know it is not in topic, but I ask if is possible in the future to change superdrive with another or to add a second drive from a pc, like a plextor dual + dL dvd burner (it is 716al ide, with slot loading, maybe it helps with mac bezel). I'm not a mac user now, but I really like the mac pro and also like the possibility to put my hands inside the computer, so the mac pro is the best candidate to be my future buy. If I must write in another topic, please tell me, and apologize for my bad english.
Bye.

no....... dont over clock 4cores when you could have 8!!!!!!!!

lol
look that this some guy has got a mac pro and some kentsfeild quad core samples and shoved 'em into it

http://anandtech.com/mac/showdoc.aspx?i=2832&p=6

I don't know about the Xeon processor, but on PC's the Core 2 Duo has exceptional overclocking value. Conroe class Core 2 Duo's (3.0 GHz Clock, 1066 MHz FSB) were shown to overclock very well on high-end MB's by setting the FSB to quad-pumped 200 MHz (instead of 266) and modifying the chip voltage, up to 4.0 GHz while still using air-cooling, or up to 5.4 GHz with liquid nitrogen cooling! Even though Core 2 Duo comes in Desktop and Mobile Class flavours, while Xeon is Server Class only, the Xeon (I'm talking about the new Woodcrest of course) is basically a suped-up version of the Core architecture, so I think it would react very well to overclocking. Now, I know overclocking isn't the same thing on PC's than it is on Mac's, but if someone finally finds a way to mess with EFI, I think the MacPro could be a true overclocking beast, like all Intel Macs.

nope, efi, and even with bios mobos if it came from apple (or any oem....) you cant overclock.....

At this moment, no, but when EFI becomes mainstream (if it does), since most mac owners which is only where efi is mainly used don't want to overclock theres no community for it. Also, yes you can change your superdrive, but make sure its a pioneer since those are best supported by OS X.

pin mod is possible.

Pin mod ? can you tell me some more info ?

Does anyone make a software overclocking alternative for OSX?

someone should find the clock ic and send it to the clockgen maker - maybe it is possible through windows

on core2's if 2 pins are shorted out the cpu will trick the board into thinking it is a 1333mhz chip insted of a 1066

overclocking + EFI = probably incompatible

I've done it guys!
More info here:

http://www.o0o.it/pro/

See ya!

I'm not an overclocker, but looks nice.

Here is something interesting.

A Power Mac Dual Xeon 3.0Ghz overclocked under Windows.
But not yet posible under OS X

http://forum.hardmac.com/index.php?showtop...&#entry4358

Now it's possible to overclock a Mac Pro.
Read here: http://www.zdnet.de/enterprise/mac/

Click on the screenshot

These Xeons use the same cores as the core 2 duos, however they are tweaked and such to get a higher rate of performance, or reliabilitiy. The actual CPUs, could have some potential. However, seeing with even the MacPro overclocking program, the most you could get out of it and still remain stable is around 3.2 ghz from 2.8. Which is terrible for a current Intel cpu. It also depends on what stepping these cpus are using.

The 45nm intel CPU's have about the same potential between desktop and server flavors (LGA 775 and 771 sockets, respecitively). This means that we could expect around 4GHz on a properly setup Mac Pro. The reason we are not seeing 4GHz is simply because the FBDIMM based memory is the weakest link and current overclocking methods for the Mac Pro overclocks the almost the ENTIRE system

There has to be a way to just overclock the processor/FSB. We have everything on the internet from some manufacturer to eliminate the memory barrier.

As a second idea, I'd like to add one final suggestion for anyone crazy enough to try. As a disclaimer, I take no responsibility for any damage whatsoever. Just program the SPD on a single 800MHz DIMM to DDR2-667, which may or may not force the system to a lower speed (like DDR2-640). Then crank up the FSB. Assuming that everyone was getting 925MHz out of their 800MHz FBDIMMs then 925/800 = 14% overclock. So 900/640 = 44% overclock. This means that your 2.8GHz could go up to 4.04 GHz before hitting the FBDIMM wall again(with 925MHz memory). This is inherently dangerous and tedious. Any wrong bit set means death to (at least) that DIMM until you can program it back (which may or may not be possible). Another program is that SPD's can be locked in the factory, which means no go.

As always with being a pioneer, theres risks that you will run into before hitting the prize:
Voiding warranty
Killing system (due to programming a SPD)
Murphy's Law

GL

Although traditionally server parts OC better than desktop parts, this doesn't seem to be the case with Intels latest offerings; everything seems to be equal (perhaps intel is just having insane yields). Most of the Quad-core 45nm parts haven't been able to hit 4GHz except for the extreme variants, but 3.2 should be easy to surpass. If I had to guess, the limiting factor is probably the motherboard or RAM not being able handle the increase in FSB clock.

The Quad cores are more difficult to overclock then a good dual core indeed. I can say that the FBDIMM motherboards have unprecedented signal integrity since they are not eco desktop boards and feature an cleaner serial memory interface, and most overclocking issues are from the FBDIMMs themselves (keep in mind that the serial interface on a FBDIMM is approaching 6Gbit per trace when they start to fail (effective 6GHz clocked data)).

On a side note, there are two LGA 771 motherboards that can be overclocked in the BIOS. One is skulltrial and the other is made by Asus (I cannot remember the name).

It is more difficult to overclock 4 cores than it is to overclock 2 cores, but with Intel, overclocking quad cores is made easy. The q6600 can go about 3ghz +, which is really good for a quad core.

I wouldn't bother with the ZDNET software it doesn't actually work!

I ran it, changed the speed and ran the speed test software. It didn't make a blind bit of difference!