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Overclocking Mac Pro

DLary said:
No luck at all on my 2.66 mhz MacPro 1,1

Even with only one speed bump, My machine will not boot, just a flashing power light. Maybe this doesn't work on older MacPro's? Maybe my memory is not so good? I have 2GB Apple and 2GB Crucial Technology.
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I got the same thing last night, I left it on and I woke up this morning to discover a nice little kernel panic.
 
--Diatribe begins--
Why?

Some of us are hobbyists that came over from the PC side, Some of us are gamers, we like to mess around with our computers. I don't understand why some people seem to take offense at this. Some out there seem to think if you are not one of a select group of ever so special "professional" users, we should not be allowed to own "professional" Macs.
--Diatribe ends--

I read that first generation MacPros cannot reboot after being overclocked. I am not really sure that any thing is happening at all. GeekBench and XBench scores remain essentially the same before and after overclocking.

Anyone know of a utility that will report back actual processor and bus speeds?
 
christoh said:
If you experience a kernel panic after about 5 minutes @3200 MHZ, ckeck your RAM for parity errors using the Console (Applications - Utilities - Console) or check /var/log/system.log in any other way.
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Hi Cristoph

Yes, I was watching the console at the time, and did notice the parity errors (not just immediately after the change, but later also, in small groups). 3.2 must be too high for my system, but 3.0 is fine. Thanks for writing the program!
 
christoh said:
@aLoC:

If you experience a kernel panic after about 5 minutes @3200 MHZ, ckeck your RAM for parity errors using the Console (Applications - Utilities - Console) or check /var/log/system.log in any other way.

In the Console select "all messages" or "system.log". Then set your CPU clock to 3200 MHz. You should notice some RAM related messages immediately, which is normal.

Then run any form of stress test, e.g. Geekbeench. If you get more RAM-related errors (parity or correctable fbd) better RAM will probably help. If you don't get these errors, other components (CPU, FSB, MCH, etc.) are the cause for the panic.

Our test machines worked fine @3178 MHz with Apple-RAM and @3241 MHz with Transcend or Kingston.

-Christoph (Author of ZDNet Clock)
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Thankyou Christoph for writing this program and providing it as freeware!!! Absolutely fantastic!
 
how can you tell that ZDNet Clock is actually changing the speed, everything I look at still says it's at 2.66. how can I verify it's doing something?

p
 
Wow! Awesome find. Just popped it on my Mac Pro 2.66 quad, cranked it up to 3.1ghz and it's running solidly for the last hour. 5gb of cheap ram too.
 
parkie said:
don't have windows installed, is there anything for mac I can use

p
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Short Answer: No!

There might be a Unix utility that you can install via MacPorts but I haven't looked myself, yet. Neither GeekBench or System Profiler will report the modified clock speeds.
 
Don't know if it's been mentioned, but overclocking is 100% safe, so long as you don't increase the voltage. Voltage increases shorten the lifespan of a CPU and greatly increase heat output... overclocking doesn't shorten the life, and the thermal increase is minimal.
 
Chilz0r said:
Short Answer: No!

There might be a Unix utility that you can install via MacPorts but I haven't looked myself, yet. Neither GeekBench or System Profiler will report the modified clock speeds.
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I've also run x-bench and I got a better score at stock speed than the so called overclocked speed. Until I see proof that it's actually doing anything I don't believe this works. I also ran windows under vmware and it said the chip was running at 2.66 (stock speed).

p
 
FF_productions said:
Keep us updated if it panics or not...mine can barely go past 2.7 without freaking out...after reading console it gave me what would seem to be Ram Errors.
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Still humming along.
And as an added bonus, started up my rebuilt turbo RX7 in one shot :D Great day for Macs and rotaries alike.
 

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parkie said:
how can you tell that ZDNet Clock is actually changing the speed, everything I look at still says it's at 2.66. how can I verify it's doing something?
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The clock in the upper right corner is apparently running faster. According to Wikipedia, these are the potential disadvantages:


Disadvantages
Many of the disadvantages of overclocking can be mitigated or reduced in severity by skilled overclockers. However, novice overclockers may make mistakes while overclocking which can introduce avoidable drawbacks and which are more likely to damage the overclocked components (as well as other components they might affect).

General
These disadvantages are unavoidable by both novices and veterans.
The lifespan of a processor is negatively affected by higher operation frequencies, increased voltages and heat. Some Overclockers argue that with the rapid obsolescence of processors coupled with the long life of solid state microprocessors (10 years or more), the overclocked component will likely be replaced before its eventual failure. Also, since many overclockers are enthusiasts, they often upgrade components more often than the general population, offering further mitigation of this disadvantage.
Increased clock speeds and/or voltages result in higher power consumption.
While overclocked systems may be tested for stability before usage, stability problems may surface after prolonged usage due to new workloads or untested portions of the processor core. Aging effects previously discussed may also result in stability problems after a long period of time.
High-performance fans used for extra cooling can produce large amounts of noise. Older popular models of fans used by overclockers can produce 50 decibels or more. However, nowadays, manufacturers are overcoming this problem by designing fans with aerodynamically optimized heatsinks for smoother airflow and minimal noise (around 20 decibels). Some people do not mind this extra noise, and it is common for overclockers to have computers that are much louder than stock machines. Noise can be reduced by utilising strategically placed larger fans which deliver more performance with less noise in the place of smaller and noisier fans, by using alternate cooling methods (such as liquid and phase-change cooling), by lining the chassis with foam insulation, and/or by installing a fan controlling bus to adjust fan speed (and, as a result, noise) to suit the task at hand. Now that overclocking is of interest to a larger target audience, this is less of a concern as manufacturers have begun researching and producing high-performance fans that are no longer as loud as their predecessors. Similarly, mid- to high-end PC cases now implement larger fans (to provide better airflow with less noise) as well as being designed with cooling and airflow in mind.
Even with adequate CPU cooling, the excess heat produced by an overclocked processing unit increases the ambient air temperature of the system case; consequently, other components may be affected. Also, more heat will be expelled from the PC's vents, raising the temperature of the room the PC is in - sometimes to uncomfortable levels.
Overclocking has a risky potential to end in component failure ("heat death"). Most warranties do not cover defunct units that result from overclocking activities. Some overclocker friendly motherboards offer safety measures that will stop this from happening (eg limitations on FSB increase) so that only voltage control alterations can cause such harm. It could be argued, however, that incremental voltage changes have very little chance of damaging components as any signs of instability would manifest themselves beforehand.
Technically, overclocking a PC component may void the component's warranty (depending on the circumstances under which the component was sold).
Potential fire risk if devices are not properly cooled.

Incorrectly performed overclocking
Increasing the operation frequency of a component will increase its thermal output in a linear fashion, while an increase in voltage causes a quadratic increase. Overly aggressive voltage settings or improper cooling may cause chip temperatures to rise so quickly that irreversible damage is caused to the chip causing immediate failure or significantly reducing its lifetime.
More common than hardware failure is functional incorrectness. Although the hardware is not permanently damaged, this is inconvenient and can lead to instability and data loss. In rare, extreme cases entire filesystem failure may occur, causing the loss of all data.[9]
With poor placement of fans, turbulence and vortices may be created in the computer case, resulting in reduced cooling effectiveness and increased noise. In addition, improper fan mounting may cause rattling or vibration.
Improper installation of exotic cooling solutions like liquid or phase-change cooling may result in failure of the cooling system, which may result in water damage or damage to the processor due to the sudden loss of cooling.
Sometimes products claim to be intended specifically for overclocking and may be just decoration. Novice buyers should be aware of the marketing hype surrounding some products. Examples include heat spreaders and heatsinks designed for chips which do not generate enough heat to benefit from these devices. (Memory chips, for example)

Limitations
The utility of overclocking is limited for a few reasons:
Personal computers are mostly used for tasks which are not computationally demanding, or which are performance-limited by bottlenecks outside of the local machine. For example, web browsing does not require a very fast computer, and the limiting factor will almost certainly be the speed of the internet connection of either the user or the server. Overclocking a processor will also do little to help speed up application loading times as the limiting factor is reading data off of the hard drive. Other general office tasks such as word processing and sending email are more dependent on the efficiency of the user than on the speed of the hardware. In these situations any speed increases through overclocking are unlikely to be noticeable.
It is generally accepted that, even for computationally-heavy tasks, speed increases of less than ten percent are difficult to discern. For example, when playing video games, it is difficult to discern an increase from 60 to 66 frames per second (FPS) without the aid of an on-screen frame counter. In such cases it does however usually allow the possible usage of higher image quality (so called eye candy) settings. The difference can also be between playable and unacceptable depending on the situation.
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OK im a noob with this, what kind of results would you see?

Faster rendering in FCP? Encoding? If so im all over it.
 
DLary said:
No luck at all on my 2.66 mhz MacPro 1,1

Even with only one speed bump, My machine will not boot, just a flashing power light. Maybe this doesn't work on older MacPro's? Maybe my memory is not so good? I have 2GB Apple and 2GB Crucial Technology.
Click to expand...

The older Intel MacPros (2006 to 2007) won't boot at all, after overclocking. You can use ZDNet Clock (our 2,66 GHz runs stable @3,104 GHz), but your real time clock will run faster too.

We are trying to find a solution for this, but Apple's Documentation doesn't cover timing issues at all.

-Christoph
 
aygie said:
OK im a noob with this, what kind of results would you see?

Faster rendering in FCP? Encoding? If so im all over it.
Click to expand...

Anything that max's a single or multiple cores would benefit from overclocking. Example: heavy duty compiling, gaming, distributed computer (Folding@Home, Seti@Home), encoding or transcoding high resolution video (especially H.264), etc.

Unless you are getting a decent overclock, you probably won't see much real-life difference. Maybe shave a few seconds off a video encode, or add 1 or 2 fps in your game.
 
parkie said:
how can you tell that ZDNet Clock is actually changing the speed, everything I look at still says it's at 2.66. how can I verify it's doing something?

p
Click to expand...

Run a benchmark using a stopwatch, e.g. GeekBench or Cinebench. That's all you can do right now with the MacPro 2006 model. Maybe, we can find a solution to tell Mac OS X to adjust the real time clock for a higher bus clock. But we haven't found a solution yet.

-Christoph
 
Why overclock? Because I've been running simulations for the past 2 months on 7 of my 8 processors utilizing an average of 97.1% of the CPU each. If I can boost my speed up to 3.2 GHz from 2.8, that's a 14% increase in speed. The easy ones take around 40 hours. This would reduce them to 35 hrs. On simulations that take 350 hrs (about 2 weeks), that cuts 2 full days off the time needed for each simulation. With over 150 done so far (the easy ones) and many dozen more to go (the harder ones), overclocking could save me a few weeks of time.
 
The tool will not brick a 1,1 you just have to hold the power button down until it powers down, then restart. When you restart, the overclock settings are set back to normal. This tool definitely makes my clock run faster, I'm not sure about anything else as Mac benchmarking tools are not very good.
 
CorneredBeast said:
Are you saying that the utility will brick a 1.1?
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Of course you can reboot a 1,1 by turning it off (graceful shutdown) and on again. However, for the real time clock to correctly adjust to the bus frequency, it must be rebootet without a shutdown, otherwise it boots up at the default speed again.

-Christoph
 
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