Is the iMac G5 processor watercooled?

Discussion in 'Macintosh Computers' started by Spanky Deluxe, Jun 23, 2005.

  1. Spanky Deluxe macrumors 601

    Spanky Deluxe

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    #1
    I was just wondering if it was or not, since the big boy powermacs are.

    If its not then there's a good chance that the 2.0Ghz iMac actually has the same processor as the 2.5/2.7Ghz Powermacs since the whole watercooling is there because the processors are already overclocked.

    Also, another thought on a slightly different tangent, do you reckon that Apple might use their insight into liquid cooling on the G5s to get the edge on the common Dell and HPs when they shift to x86 systems? If they cool them with water and overclock them from the start then they will always have a system with 10-30% better performance than their competitors. Smart move?


    Phil
     
  2. mad jew Moderator emeritus

    mad jew

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  3. Spanky Deluxe thread starter macrumors 601

    Spanky Deluxe

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    Aha, makes you wonder if there could be any way to watercool an imac and get G5 Powermac processor speeds. {Sorry, I live in a hardcore PC overclocking world}.
     
  4. mklos macrumors 68000

    mklos

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    Liquid Cooling is not a very good way to cool things IMO. The liquid cooling in the PowerMac is only gaurenteed for 2 years by the creator of the cooling system (Delphi Automotive) without leaking. Plus, its incredibly expensive for Apple to do. They wouldn't even use it if they didn't have to.
     
  5. mad jew Moderator emeritus

    mad jew

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    #5

    It'd be nice, but you'd have trouble fitting any liquid cooling systems into an iMac enclosure. And that's before you manage to over-clock the G5 in the first place.



    When Apple move to Intel, they won't be using G5s. However, it'd be pretty cool if they still used liquid cooling to get better performance than regular Dells etc.
     
  6. MacTruck macrumors 65816

    MacTruck

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    So which units have liquid cooling. I am guessing the following:


    G5 Dual 2.3ghz
    G5 Dual 2.5ghz
    G5 Dual 2.7ghz
     
  7. mad jew Moderator emeritus

    mad jew

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    #7

    I don't think the 2.3GHz machines have liquid cooling, from memory.

    See here for a little more info. :)
     
  8. psycho bob macrumors 6502a

    psycho bob

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    Where do people get the idea that the 2.5 was an overclocked 2GHz from? The watercooling has nothing to do with overclocking it is to do with the density of the chips and there fore the heat produced from them. The liquid can carry more heat away allowing for better dissipation through a radiator than a purely air driven system would allow for whilst maintaining acceptable noise levels.
     
  9. wdlove macrumors P6

    wdlove

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    #9
    Only the Rev. B 2.5 and the newest Rev. C are liquid cooled.


    I don't think that Apple would use Liquid cooling if it didn't work. This is the first time that I heard that it's lifetime was only 2 years. AppleCare would cover the cooling for a full three years.
     
  10. sacear macrumors 6502

    sacear

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    No Macs are "water" cooled, yet some Power Macs are liquid cooled

    No. No Macs are "water" cooled.

    I know it's nit-picky, yet that is a pet-peeve of mine. The only time Macs are water cooled is when someone spills their cup of water into it.

    Water could not cool a processor, it could not cool and condense fast enough in that small a system. I believe that the liquid is a fluid similar to automobile anti-freeze.

    Apple does not "over-clock" its CPU chips. The speed rating of the processor chips is rated by the manufacture at the factory. Apple uses that rating.

    The reason Apple is using liquid cooling in the 2.5GHz and 2.7GHz Power Mac machines is due to the extreme heat produced by those PPC 970 chips as manufactured and rated by IBM.
     
  11. JeffTL macrumors 6502a

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    #11
    Liquid cooling is not something you do if you can help it -- but G5s run so hot that at 2.7 GHz, liquid evidently becomes the best way to handle the cooling dilemma.
     
  12. sacear macrumors 6502

    sacear

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    #12
    G(x) is Apple's moniker, not IBM's or Motorola's

    The Gx moniker is Apple's, not IBM's nor Motorola's nor Freescale's. Apple made up the Gx moniker to name the generation of Power Mac computer, that being the third generation (G3) at the time. Subsequently and secondarily, the CPU was also given the Gx moniker. Apple may choose to continue the Gx moniker.

    When Apple moves to Intel, they won't be using PowerPCs. Apple might name its next CPU with an Intel processor the G6.
     
  13. sacear macrumors 6502

    sacear

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    #13
    Only the 2.5 and 2.7 GHz machines have liquid cooling, not the 2.3

    That is correct. The 2.3GHz machines do not have liquid cooling. Only the 2.5GHz and 2.7GHz machines have liquid cooling.
     
  14. mad jew Moderator emeritus

    mad jew

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    #14

    Please reread, I was talking about G5s. I will place a large sum of money on the fact the new Intel-based processors will not be called G5s!
     
  15. eXan macrumors 601

    eXan

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    #15
    Only 2.5 and 2.7 are liquid-cooled
     
  16. skubish macrumors 68030

    skubish

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    #16

    You should know what you are talking about before having a pet peeve. Automobile antifreeze is 90% water 10% ethylene glycol. The glycol is in there to prevent freezing and thats it. Compared to air, water is an excellent coolant.

    Furthermore, there is no condensing of the liquid. It just flows across the CPU, picks up heat and then the liquid is cool as it passes thru a radiator. The inlet temperature and outlet temperature don't vary more than a couple of degrees. Air conditioning systems involve a phases change (liquid to gas). Car cooling systems do not involve a phase change (the antifreeze is always liquid).

    Phase change cooling is more effect but it requires high pressure.
     
  17. Daveway macrumors 68040

    Daveway

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    #17
    It costs Apple $50 for water cooling per unit.
     
  18. Spanky Deluxe thread starter macrumors 601

    Spanky Deluxe

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    #18
    A watercooling kit really doesn't cost that much and lets face it, Apple's 'liquid' cooled system is basically just a 'water' cooled system.

    Sacear: A 'rating' of a cpu can be anything you want. Most processors are rated to a certain level or speed under air cooling. That's just the norm. Yes the 2.5Ghz chips could be rated at 2.5Ghz with liquid cooling but should they be rated for air cooling, they'd probably be around 2.0-2.1.

    From my experience, a 2.2Ghz chip will reach speed of about 2.7-2.8 Ghz under decent water cooling whilst it should reach 3.0-3.1Ghz under phase change cooling. (Phase change is essentially what a refrigerator or freezer uses). My experience is solely based on Athlon XP-M and Athlon 64 chips although the maximum kind of percentage gains is generally equal amongst Intel, AMD, Via, Cyrix, IBM and whatever other chipmakers there are out there. Its just the way electronics work.
    This is why I say that the 2.5Ghz G5 chips could actually be the same chips as the 2.0Ghz ones only watercooled and hence 'rated' higher. Its more likely that the 2.5s are off of the same wafers as 2.2s though, since a manufacturer produced watercooling - sorry, liquidcooling solution would most likely have less gains than a custom built one.
     
  19. mad jew Moderator emeritus

    mad jew

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    #19

    So put the G5 in the fridge and it'll finally reach 3.0GHz?

    Or do you need to make changes to the actual chip too?
     
  20. Daveway macrumors 68040

    Daveway

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    #20
    Considering it's a G5, you may want to try a freezer.
    'Yall act like simple water cooling is extreme. Check out what these guys did. ;)
     
  21. Spanky Deluxe thread starter macrumors 601

    Spanky Deluxe

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    Lol, well depending on the actual speed of the chip used in the top end G5s it might be possible. If the highest end chip that is air cooled is the 2.3Ghz then some of them could possibly hit 3Ghz under phase change. However, PowerPC based chips are notorious for not being as 'overclockable' as x86 based chips. Its probably because x86 based chips have to put up with much much worse computer designs because of all of the thousands of horrible OEMs out there, so they're designed to 'put up with worse' cooling setups. If Apple were to release a 2.5Ghz air cooled G5 then I'm sure that it could reach 3Ghz under phase change. All I know for sure though is that my 2.2Ghz Athlon 64 3700+ chip runs happily at 3Ghz under my phase change 24/7 which makes it equal to a 5000+ Athlon or a P4 5 Ghz. Hence why my main system will remain a PC for a while yet. :(
    Phase change doesn't exactly work by 'putting it in a fridge', its more like putting little piece of metal that has the cooling power of an entire freezer behind it on top of just the CPU, i.e. you're only cooling the processor. So for a dual system, you'd need two coolers.
    When the x86 based Macs come out I have no doubt that there will be more overclocking going on in the Mac world.
     
  22. mad jew Moderator emeritus

    mad jew

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    #22

    Classic! Reckon it'll fit in the mini enclosure?

    No, wait. Better yet, the next PowerBook!

    Coolness. :cool:
     
  23. Spanky Deluxe thread starter macrumors 601

    Spanky Deluxe

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    #23
  24. mattster16 macrumors 6502a

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    Exactly, glad someone beat me to it so I didn't have to explain all that. This person was thinking of an AC system. That would require some kind of noisy compressor, that would just kill the powermacs reputation for being quiet. :p

    To put it simply the 'water' just transfers the heat from the processor more efficiently then is possible in a strictly air cooled setup.
     
  25. sacear macrumors 6502

    sacear

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    #25
    Apple could call NeXT Power Mac G6

    Umm, yeah, of course. That is what I said. No one said they would be called G5s. Yet, the next Power Mac model (with Intel processor) could still be called G6.

    So, could Apple call the upcoming Intel based Power Mac the "G6?" Well, they could. If they want to. The moniker Gx is Apple's and refers to the Power Macintosh model first and predominantly, and secondarily to the CPU. The CPU was named after the Power Mac model moniker. At this particular time the fifth generation Power Mac just happens to coincide with the fifth generation of PowerPC.

    The next generation of Power Mac will still be the sixth (G6), no matter what they call it and no matter what processor is inside. Apple could easily call the new Intel processor based CPU "G6," if Apple uses the sixth generation of some Intel processor (hmm, P6 in the G6?) The Pentium itself was the fifth generation of Intel's x86 processor (80586, i586, P5), the Pentium Pro, Pentium ||, Pentium |||, and Pentium M are the P6, (Pentium M P6 in the Power Mac G6? PowerBook Yonah?) hmm.

    So the next machine itself will still be a sixth generation Power Mac (G6). However, Apple may decide to change the naming scheme partially or altogether completely.
     

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