[qwerty2]

Check it out and use Sherlock or Watson to translate if you can't read French. It's under this title: 2004-08-24 - G5 2.5 overclockés

http://croquer.free.fr/

What do you think? IBM has been having such problems that I find it is easy to believe this. What if Apple only had a 2.2 GHz to show from last year all the way up until now? That would have been a total disaster and would be motivation for overclocking a 2.2.

[djohnson]

Originally posted by qwerty2:


http://croquer.free.fr/

[Catfish_Man]

Of course, IBM says it's speced to run at 2.5GHz, but what do they know?

[qwerty2]

Originally posted by djohnson:

Well, I agree -- there is no proof and it is likely just a ploy to get easy hits. (If that's what you mean by the roll eyes.) I wonder if this can be easily proven false?

[qwerty2]

Originally posted by Catfish_Man:
Of course, IBM says it's speced to run at 2.5GHz, but what do they know?

Since it is IBM who is having all the trouble that is delaying Power Macs excessively, isn't that a little like the proverbial "fox guarding the hen house" to say we are to trust that it's a "true" 2.5 because IBM said it is? Then again, I know of no other way to confirm or deny that it is what it is except to go along with what IBM says.

[Link]

They're just trying to score hits. There's always been rumors flying around because some moron posted the same thing about dual 1.42s but that's just not true.

Apple isn't that stupid. IBM PROBABBLY wouldn't let them sell overclocked processors marketed as such to begin with. Sure one can point at the cooling system but that's just to keep it running *SILENT*. Then again apple forgot one of the biggest heat producers in the g5 with that water cooling monster --- the system controller

[Catfish_Man]

Originally posted by Link:
They're just trying to score hits. There's always been rumors flying around because some moron posted the same thing about dual 1.42s but that's just not true.

Apple isn't that stupid. IBM PROBABBLY wouldn't let them sell overclocked processors marketed as such to begin with. Sure one can point at the cooling system but that's just to keep it running *SILENT*. Then again apple forgot one of the biggest heat producers in the g5 with that water cooling monster --- the system controller

Actually iirc the water cooling system helps cool the system controller as well. I can't remember where I read this though. The main reason for the water cooling seems to be that a 2.5GHz 970fx dissipates 50 watts over 66 mm^2, while a 2GHz 970 dissipates 66 watts over 118 mm^2 (iirc). Less heat total, but much more per mm^2 (I'm pretty sure we had this discussion on this forum recently though...)

My main issue with people saying chips are "overclocked" is that overclocking means running it faster than its rated speed. The manufacturer can rate it at whatever speed it'll run at. The only way it could be overclocked is if Apple was running it faster than IBM rated it, but we know that IBM rates it at 2.5GHz. There do seem to be some system life span issues at high voltages for the 970fx though, so I suppose running it at those could be considered something like overclocking.

[Maflynn]

I always thought the 2.5 was an overclocked 2.0.

IBM was unable to produce a 3GHz and they are having yield issues with their fabrication plant, and apple installed a water cooling rig inorder to make it silent. What about all of those claims apple made that they put in 9 fans that run at low speed so that the G5 would be quiet.

It would seem to me that if someone wanted to overclock a 2.0GHz they would want a water cooling system installed since that beast would probably melt into a puddle of slag w/o it.

Mike

[Eug Wanker]

What is it with this infatuation with claiming Apple uses overclocked chips? This has been claimed with a bunch of different chips Apple has used, and every time these claims have been proven wrong.

Note also that IBM freely publishes info about their 2.5 GHz parts:



BTW, croquer is a complete waste of time, not just with their current overclocking article, but with all of their articles.

[EMC]

It's not like IBM built a 2.2Ghz processor and overclocked it. You don't build a clock speed into a design. IBM builds lots and lots of G5s, about which only 1/4th work. Of the working chips, each one is tested at a variety of clock speeds. The chips which function over 2.5 Ghz, get put in the 2.5Ghz bin. The ones that fail above 2.0 Ghz get put in the 2.0Ghz bin. Once they've determined this, Apple hardwires the motherboard to run a clock rate compatible with these chips.

Overclocking is the process of raising the clock rate above spec. Any one of the 2.5 Ghz chips might be capable of being run at a higher speed. IBM just knows that raising the clock speed will on the average cause to many chips to fail. So, if you overclock your proc, you might find you were lucky enough to get one of these better manufactured chips. Unfortunately, while these higher speeds may function initially, they can also heat of the chip to higher temperatures, and heat exponentially increases the electron transport of the copper wiring on the chip itself, causing it to literaly dissolve away much faster and break the chip.

Thus, if the 'water-cooled' heat pipe can disperse more heat than a traditional fan, it is possible that the chips can be run at a higher rate than with conventional cooling. Still, they are not 'overclocked' in the traditional sense. IBM just approves their use at 2.5Ghz so long as they are appropriately cooled

[Maflynn]

Originally posted by Eug Wanker:
What is it with this infatuation with claiming Apple uses overclocked chips?

Well for me, I wouldn't catorgize it as a infatuation.
Based upon the what I see from IBM and Apple. I think that either IBM really has heat issues with the G5 or Apple OC'd the hell out of the 2.0.
I cannot understand why apple would install such a complex and expensive cooling system just in the name of quiet there's more to the story.

Mike

[MacNStein]

Correct me if I'm wrong here, but it's only considered "overclocking" when the end user is manipulating the processor frequency beyond it's "bin" rating. By the term's very nature, it's not possible for a manufacturer to overclock anything.

[BrunoBruin]

Croquer also claimed, in May, that Apple would unveil PPC975-based Power Macs at 2.2, 2.4 and 3.0GHz at WWDC.

[Eug Wanker]

Originally posted by Maflynn:
Well for me, I wouldn't catorgize it as a infatuation.
Based upon the what I see from IBM and Apple. I think that either IBM really has heat issues with the G5 or Apple OC'd the hell out of the 2.0.
I cannot understand why apple would install such a complex and expensive cooling system just in the name of quiet there's more to the story.

Mike

If you look at the IBM specs for the chips, the 2.5 puts out no more heat than the 1.8 GHz G5 970. In fact, the G5 2.0 970 is hotter than the G5 2.5 970FX. If you look at the above graph, IBM pegs the max power of the 2.5 at 100 Watts, which is toasty, but not unreasonably so. Intel chips are currently in the 130 Watt range.

However, the 90 nm 970FX chips are much more dense, because their die size is very small. Conventional cooling has trouble dealing with high heat density, even if the overall heat isn't increased. I posted more on this here.

[fiesta cat]

Originally posted by qwerty2:
Since it is IBM who is having all the trouble that is delaying Power Macs excessively, isn't that a little like the proverbial "fox guarding the hen house" to say we are to trust that it's a "true" 2.5 because IBM said it is? Then again, I know of no other way to confirm or deny that it is what it is except to go along with what IBM says.

We are talking about machines around $3000. Some of the 64-bit/PPC based servers that IBM sells start at $30,000, and some setups can easily top $300,000.

I don't think IBM would play fast and loose with numbers on the G5s. If they did, and were caught, they wouldn't be concerned about a bunch of pissed of Mac owners, they'd have larger problems, namely those IT managers who spend $100,000s and more every year who would be questiong the rest of their 64-bit/PPC lineup.

[booboo]

Originally posted by BrunoBruin:
Croquer also claimed, in May, that Apple would unveil PPC975-based Power Macs at 2.2, 2.4 and 3.0GHz at WWDC.

Well maybe Croquer were right - just premature ;-)

[deboerjo]

I don't think many of you understand what "overclocking" means, particularly based on querty2's statement. Read EMC's post. If a chip meets certain specifications, and is operated within those manufacturer's specifications, it's not overclocked. Overclocking means running a chip outside of it's specifications. IBM has set the specifications for the G5 2.5GHz. Apple is meeting those specifications. By definition, no overclocking is involved.

Now, maybe it's more accurate to say IBM is pushing the limits of the design to get it up to those speeds, much like what Intel did with the 600MHz Katmai, and the 1GHz/1.13GHz Coppermine Pentium IIIs, and is doing now with the Pentium 4s. What I mean by this is they raise the voltage and lower the maximum safe operating temperature specification. For example; early coppermine Pentium IIIs have a Tmax of 82 degrees C, and a specified voltage of 1.6V. That means the computer manufacturer is required to ensure that the processor temperature never rises above 82 degrees, and the motherboard has to supply 1.6V (+/- 2.5%) power. As the Coppermine pushed past 1GHz, Intel lowered Tmax to 62 degrees, and the specified voltage went up to 1.75V. Many people at the time called this an "Intel-certified overclocking". Again, by definition, this is not the case. However, it did demonstrate that Intel was under intense pressure from AMD at the time and was shipping products that were not entirely polished. Ultimately the first batch of 1.133GHz Pentium IIIs were recalled. I don't think IBM is going to quite such extremes as what Intel did in that example, but I'm fairly sure the 2.5GHz G5 has a lower Tmax and higher Vcore specification than the 2.0GHz parts.

-Jon

[Scotttheking]

Originally posted by qwerty2:
Since it is IBM who is having all the trouble that is delaying Power Macs excessively, isn't that a little like the proverbial "fox guarding the hen house" to say we are to trust that it's a "true" 2.5 because IBM said it is? Then again, I know of no other way to confirm or deny that it is what it is except to go along with what IBM says.

Erm, IBM ships it rated to run 2.5GHz. It runs at 2.5GHz. Thus, it's a 2.5GHz chip. If a chip it rated to run at a speed, marked accordingly, and it runs at that speed, it isn't over-clocked.

[Maflynn]

But thats not what we are saying. I believe that apple and/or ibm are using 2.0's in the 2.5 and that's the reason why they had to put a liquid cooled unit into the box.

Mike

[Catfish_Man]

Originally posted by Maflynn:
But thats not what we are saying. I believe that apple and/or ibm are using 2.0's in the 2.5 and that's the reason why they had to put a liquid cooled unit into the box.

Mike

All evidence so far (Apple and IBM's public statements, as well as logic) is against that, but there's no real harm in you believing it.