Turn off hyper-threading on my i7?

Discussion in 'iMac' started by MythicFrost, Jan 31, 2011.

  1. MythicFrost macrumors 68040

    MythicFrost

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    #1
    Hi,

    I'm wanting to turn off hyper-threading on my i7, in order to reduce the temps in the computer. Does the i5 run cooler than the i7? (I'm assuming it does) (09 model), I would like it to be overall cooler.

    And, if this is possible, is it easily turned off?

    Thanks
     
  2. simsaladimbamba

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  3. MythicFrost thread starter macrumors 68040

    MythicFrost

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    #3
    With unmodified fans, about: ~60c for HD, 45-55 for CPU, 50-55 for GPU, etc.
     
  4. simsaladimbamba

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    #4
    That sounds more than okay, I have the same temperatures in my 2007 iMac with a C2D CPU, except that the HDD is only about 46° C.

    The i7 can take much more heat anyway and the aluminium back of the iMac is a good heat dissipater.
     
  5. MythicFrost thread starter macrumors 68040

    MythicFrost

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    #5
    True, however I don't like the hard drive having such a high temperature. I just booted back to OS X from Windows 7 (I was playing a game) and the temp shows as 51c in iStat Nano (which is ok).

    I'd rather leave my fans at stock speeds (silent) than the faster (less silent) speed I'm using now, but I don't want the hard drive any more than 50c and I don't want the GPU anything >65-70c under load (it can hit 80-87 with stock fans).
     
  6. TMRaven macrumors 68020

    TMRaven

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    #6
    Stop worrying about your cpu's temperatures, there is a difference between i5 and i7, but it only makes for a few degrees of difference. There is one cause for concern and that's your hdd, it should never go above 60c. Hopefully that temp of 60c was after a long session of movie encoding or something. If not, check to see if your hdd fan ever revs up, it might be a bad temp sensor.
     
  7. MythicFrost thread starter macrumors 68040

    MythicFrost

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    #7
    It's not the CPU I care about but the hard drive / GPU. My fans run really low on stock, and never really rev up unless I'm gaming.

    The fan never really revs up, and it NEVER goes above 60c no matter what I do. Casual use, hard drive = 60c.
     
  8. TMRaven macrumors 68020

    TMRaven

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    #8
    Wait, I thought you just said you booted it back in osx and the hdd read as 51c, but now you're saying it's always 60c for casual use?
    The gpu can take temps in excess of 100c, I wouldn't worry about it at all.

    IF the hdd is always at 60c, you might pop in hardware check to see if there's any temp sensors out of line. I know my iMac has a bad sensor for the gpu I think, and it causes the cpu fans to rev up more than they should during an encode, when the gpu spikes in temperature (not really a problem, but causes for a little annoying noise)

    I know my hdd can get to 60c from time to time too after a long gaming session on windows, but if it averages around 45-50c with casual use, there's nothing to worry about.
     
  9. simsaladimbamba

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    #9
    You could always use SMC Fan Control to spin the HDD fan up a bit. Or if you are really worried, you could contact Apple and make a Genius Bar appointment.
     
  10. MythicFrost, Jan 31, 2011
    Last edited: Jan 31, 2011

    MythicFrost thread starter macrumors 68040

    MythicFrost

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    #10
    Casual use in OS X it's 60c pretty much. I was surprised to see it at 51 when I switched over.

    Fans are at stock speeds: optical: ~1150, hard drive: ~1100, CPU: ~950.
    Temps are: optical: 51, hard drive: 51, CPU: 51, GPU diode: 67 (heat-sink 63), ambient: 26

    The hard drive is unusually low, I'll leave the fans at stock speeds for a while and see if it goes back to normal.

    EDIT: Hard drive temp is 58c right now, going back to normal... just editing in XCode and listening to some music on YouTube.
    Yeah, I'm already using that. I just don't like the extra noise.
     
  11. Hellhammer Moderator

    Hellhammer

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    #11
    It's most likely the GPU that is heating up the HD. It and especially its heatsink are very close to the HD. Also, as your CPUs is running cooler than the HD, cooling down the CPU even more shouldn't have a noticeable impact on the temperature of the HD as the CPU didn't warm it up in the first place.
     
  12. MacHamster68, Jan 31, 2011
    Last edited: Jan 31, 2011

    MacHamster68 macrumors 68040

    MacHamster68

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    #12
    that are average temperatures considering everything is in such a thin small case without much room for air , and far from hot , even for a cpu ..and gpu , none of the components will die premature with these temps

    so i guess if you really want lower temp then get rid of the hdd and fit a ssd instead , then throw the logicboard with your i7 out and fit a intel atom or amd neon inside and opt for a intel GMA 950 graphics ... then you might get it cooler running, but you might lose a bit processing power in return , but what do you want processing power or cool running :confused:
     
  13. TMRaven macrumors 68020

    TMRaven

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    #13
    Nah it's not good for hdd to idle at 60c. In fact most companies rate their hdds for 60c-65c limit. My iMac's hdd idles at 40-45c, so there might be a problem. I say it's either bad sensor, bad ventilation or too hot an environment. Is the iMac in direct sun?
     
  14. MacHamster68, Jan 31, 2011
    Last edited: Jan 31, 2011

    MacHamster68 macrumors 68040

    MacHamster68

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    #14
    normally i would say you are right , but apple fits different harddrives in the same series of Mac's , and some will run hotter then others too
    the WD 250gb 7200rpm in my iMac core duo was too running at about 58 degree
    now that i have a WD 600gb velociraptor 10000rpm inside the temps hardly reach 50 degree ,
    so the choice of harddrive has a impact on the temps too
    and the harddrive will withstand much higher temperatures then 60 degree, it would be a shame ..whops 60 degree reached ..goodby harddrive , most times the manufacturers only recommend temps of xx degree , but there are tolerances planned in

    GPU diode nothing to worry it will burn out at about 100 degree
    and the cpu might shut down at 80+degrees to preserve its life
    so as long as you dont fiddle with the fans and the fans are turning a bit creating some sort of air flow , there should be no reason to worry

    why are people so obsessed with the temperatures , you got a new Mac with apple care (i hope for you) so everything is fine
    i guess nobody does trust the engineers at apple to have a clue about the hardware

    and a AIO system will always run hotter then a normal desktop due to limited airflow inside because of the small space
     
  15. Hellhammer Moderator

    Hellhammer

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    #15
    E.g. WD states that the operating temperature for Caviar Blues is from 0°C to 60°C. If the HD is constantly at 60°C, it may lead to early failure. One shouldn't be forced to buy an AppleCare due to poor cooling design.
     
  16. Detrius macrumors 68000

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    #16
    Believe it or not, this is actually very common in the silver iMacs. Additionally, it's very common for the HD fan to be bad or just not quite good enough. I've seen a lot of hard drives fail in various iMacs due to overheating.
     
  17. MacHamster68, Jan 31, 2011
    Last edited: Jan 31, 2011

    MacHamster68 macrumors 68040

    MacHamster68

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    #17
    i had that in mind ,but we are talking about apple , the rules of physic's are not important for apple

    of course its a bad design , far to cramped in the iMac's a thicker case design and some more ventilation holes some bigger heatsinks and the temps would drop by 20 degree

    it started with g5 , apple did want this hot running processor which was unsuitable for laptops in a AIO case , then to make matters worse they fitted the harddrive direct above the processor , and all apple had in mind of solving the issue was to make the case thinner ....and still leave only a small slot for heat to escape , a concept that still survives in 2011, common sense would tell everybody heat has still even in 2011 the tendency to rise so giving it as much room to escape as possible ..a angle grider at hand to make a second slot in the top would have sorted the heat issue instead of making a giant aluminium heatsink (the new iMac's )without fins outside means actually preserving the heat inside
     
  18. MythicFrost thread starter macrumors 68040

    MythicFrost

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    #18
    That's when it's not doing anything though, it can hit 55+ in Windows 7. But yeah, you're probably right, it isn't what's heating up the hard drive.
    I'm only concerned about the hard drive and GPU, nothing else. The hard drive I have heard, as said in this thread, that 60-65 is the max, therefore I am uncomfortable with it at this. I've also encountered problems with my GPU under Windows 7 in Crysis: Warhead and I believe it to be when the GPU is hitting 87c+.

    I'm wanting to lower the temps of my existing hardware if possible, as I said, not throw it out. If I wanted to get rid of it I'd sell it and buy one of the Core i3 27" iMacs. I'd love an SSD but I need a hard drive as well for storage.
    No, it isn't in direct sun. It's in an air-conditioned house with tinted windows (keeps a lot of heat from the sun out).
    I'm not obsessed but worried (and yes I have AppleCare), I don't want my hard drive at that temp as I said. I'm also concerned about the GPU hitting 87c+ in Windows while gaming, I'm pretty sure it starts to cause problems in Crysis: Warhead. Additionally, I also think the hard drive starts to throttle at ~60c and slow down.

    I'm sure they have a clue about the hardware, but that doesn't make my hard drives temp 60c temperature any less.

    I already have an AppleCare fortunately.
    Yikes...!

    Anyway, I've booted up this morning and my temps are as follows: HD 33, CPU 34, GPU Diode 46, Ambient 19, Memory Controller 36, Optical Drive 30.

    As I said, I don't think it's acceptable for my hard drive to be at 60c even when under load, yet alone average use like in my case, particularly not from 30c. And, as I said I think my GPU is causing problems when it's getting really hot.

    I like silence, my fans are all spinning at stock speeds (~1000 RPM) compared to 3400 for the hard drive, 2800 for the optical, and 1600 for the CPU.
     
  19. MacHamster68 macrumors 68040

    MacHamster68

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    #19
    the iMac has a mobile gpu , a acceptable one but still the same you find in laptops , and as crysis shows even fully fledged desktop GPU's in sli setup their limits , how you'd expect a mobile gpu to handle that in such a small confined space with a little heatsink and a tiny fan especially as the iMac is designed to be ultra quiet , near everybody is already complaining if they occasionally hear the harddrive spinning and are running disturbed and crying to the apple store if they even hear a fan :eek:
    i mean apple follows the request of customer, who do not want to hear their iMac under no circumstances, some even ask how to turn the chime of because its disturbing them in their quiet environment :confused:
    and the iMac was never designed as a gaming rig , no doubt it will handle games , but there are obvious hardware limits
    the only thing you really can do when gaming is with one or the other tool to rev up the fans to max to create some sort of airflow to cool cpu, gpu , the harddrive and logicboard as much as possible
     
  20. MythicFrost thread starter macrumors 68040

    MythicFrost

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    #20
    That's not what I'm talking about. I'm well aware these things will stress the GPU but I don't want my hard drive as hot as it is "casually", and I don't want my GPU going past 75 even under intense gaming.

    I've not really found any hardware limits with gaming, I'm not even OC'd and I can max most games at native (no AA), play Crysis: Warhead on medium/high, Metro 2033 on medium, etc.

    I've been dealing with it by using smcFanControl but it's noisy. I thought I could turn off hyper-threading, but if it won't do much there isn't any point.

    Thanks everyone for your help.
     
  21. T-bag Guest

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    Jan 20, 2011
    #21
    I got a brand new i7 iMac today, and is also experiencing high hdd temps. I had 59-60c after ripping a dvd, and 53-55 when idling. Is this safe, or should I crank up the smc?
     
  22. PhantomPumpkin macrumors member

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    #22
    I just checked on mine(although it's an early C2D gen imac) My HD, with fans at a medium speed(3k rpms) while running Seti@home, was at 32. There's definitely an issue with yours being at 60 while idle. I agree with what was said earlier, look at the fans, make sure they're working properly.
     
  23. PhantomPumpkin macrumors member

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    #23
    I'd crank up the SMC. I set mine to 3 levels(you can save settings, then just menu select).

    Default is around 1k, Mid is around 3k, and Max is max, around 5k on my machine. I usually crank it up to mid when I'm gaming, or if I am running seti@home overnight just to keep it cool. Otherwise, I can leave it at default and it's fine. It doesn't hurt to play around a bit and get them to levels you're comfortable with.

    Mine used to skyrocket on WoW. Could cook an egg on the back of that thing it seemed.
     
  24. CompanionCube macrumors regular

    CompanionCube

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    #24
    I upgraded my i5 to an i7 and it is running substantially COOLER than it did before. The i7 is an amazing processor, but they both actually have the same TDP. It probably also has to do with the very high quality TIM I used too. Disabling hyperthreading will NOT lower your temperatures.
     

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