this guy claims to have done it but it does say  much don't no if its fake or what just thought would post it http://forums.macnn.com/65/power-mac-and-mac-pro/314000/ive-overclocked-my-g5/
i hope its real lol

I have made some mounts from carbon fiber.  i will post a pic when i get home.  it is possible to OC a G5 but no one has dont it correctly.  Best bet is to contact IBM, yeah really, it has been done before with some success.

OC or not an h2o G5 would be great!  Get some pics up!!

I'm still waiting on some more supplies to come in today or tomorrow to finish mounting my water blocks in the system. I'll have pictures up as soon as I get everything installed.

After reading the overclocking article, I'm unsure it would actually work. Seems more of just driver modification than actual processor overclocking. Not sure about it since there no quanitative data to compare, just relative geusses on times for endocoding and such. Show me some benchmark screen captures, and for it to work all the time stable, and then I might be a believer. 

Might overclock the same way as the old classic macs via clock chipping. I tryed it once for giggles with a old 486PC that had a built in CPU and it did work. The CPU ran at 33MHz and I switched out the crystal that was 14.4MHz with a 16MHz one and it overclocked the CPU from 33MHz to 40MHz.

Or maybe theres a way in the firmware to overclock it. Theres so many ways theses days it's not funny.

I think they got rid of crystal clocks a while back.

This is just a guess, but maybe the OCing is done with software much like a PCs bios.  We as Mac OCers are used to the hardware OC, but PC users get full control in the bios set up.  Some boards can do it with software within the OS too.

If it is hardware, we need to look at three speed versions of the G5 chips.  That is a simplest way of finding the area for moving resistors.  It may end up being different motherboards (more likely) with changes to the bus speed as it is locked to the cpu or vice versa.

Thing is I dout apple used the same chip for all of the G5 models. Too bad you can't dump the frimware and use a hex editor to change some hardware options. Unless theres a code in OF that will overclock the CPU.

I wonder, what if you use virtual pc and use a O/C program for windows would it O/C the emulated PC CPU or will it o/c the G5 CPU.

As I have stated before, all of the chips are the same, just speed binned.  1.6-2.0 are all the same chip.  2.0-2.7 are the same too (I think they are different revisions, but I am unsure/there was a die change somewhere in the G5s.  The dual cores are all the same chip too.  I know little about OF, but there must be a way to tweak settings.  The only thing that could throw a wrench in it is differing controlling chips (like a PCs north/south bridge), which there must be with the PCI/PCIX version difference.  The G5s are just so different from anything else on the market.  We just need someone with enough money and balls to really start switching cpus around....to see what happens.


Where are the G5 cpu photos?

Photos are on their way. Just got final parts in today to mount the water blocks to the processor. I should have them up tomorrow night at the earliest. I have a soccer tournament tomorrow morning/afternoon, in Maryland so I won't be home most of the day, then Sunday I head back to college Sunday morning, so I hope to have them up by then. I have been swamped with work and have been in and out of the hospital all week with some stupid virus I caught, mono. I try my best to get pictures later tonight when I go down to the workshop in about an hour, then download and upload them tomorrow night when I get back.

Yeah, crystals are not used anymore.  Where are the pics!!!!!!!!!!!!!!?