Absolute minimum CPU temperature

Hello,

I'm interested in building a vapour phase coolant device, and I'm not able to find any information on the absolute minimum temperature that a CPU can operate at. Does anybody know of any references that give a minimum operating temperature for a given CPU?

Thanks!
Reply to Enorminous
11 answers Last reply
More about absolute minimum temperature
  1. When people do insane suicide oveclocking using liquid helium or liquid nitrogen th temps are well into the well below 0 degrees F.
    Reply to rds1220
  2. for most CPU the operating temp is -20C up to 120C, if you can make your cpu run at 0C under full load that'd be cool as hell :D
    Reply to mace200200
  3. Hey guys, thanks for the replies.

    This system is being designed as a final project in a mechanical engineering program. As part of our design, we're looking into how to make such a system consumer-ready, which means that it will have to work with a variety of CPUs.

    Given our current calculations, the temperature of the CPU heatsink will be at -10 degrees C. This doesn't necessarily mean that the CPU itself will be that temperature, but it will be very close.

    What I'm looking for specifically is a datasheet or specification sheet of some type that states that a CPU will not be damaged at -10 degrees C, or a datasheet that gives an acceptable range of operating temperatures for a CPU. I absolutely need something that I can reference.
    Reply to Enorminous
  4. I don't think any of the current CPUs have a cold bug, AMD has been showing off theirs getting crazy OCs on liquid nitrogen since the Phenom II came out, and a Sandy bridge based chip got taken pretty far on liquid nitrogen as well so you shouldn't run into any temperature issues with the GPU, just be very aware of condensation and getting the motherboard too cold, it won't take quite as kindly to extremely cold temperatures.
    Reply to hunter315
  5. Enorminous said:
    Hey guys, thanks for the replies.

    This system is being designed as a final project in a mechanical engineering program. As part of our design, we're looking into how to make such a system consumer-ready, which means that it will have to work with a variety of CPUs.

    Given our current calculations, the temperature of the CPU heatsink will be at -10 degrees C. This doesn't necessarily mean that the CPU itself will be that temperature, but it will be very close.

    What I'm looking for specifically is a datasheet or specification sheet of some type that states that a CPU will not be damaged at -10 degrees C, or a datasheet that gives an acceptable range of operating temperatures for a CPU. I absolutely need something that I can reference.



    Hi :)

    Interesting subject , which I doubt you will find any data sheets on....

    BUT....I can give you something to think about....depending on HOW you are going to cool the CPU, have you thought about "Phase change" and also about "low temperature stress fractures"


    All the best Brett :)
    Reply to Brett928S2
  6. Enorminous said:
    Hey guys, thanks for the replies.

    This system is being designed as a final project in a mechanical engineering program. As part of our design, we're looking into how to make such a system consumer-ready, which means that it will have to work with a variety of CPUs.

    Given our current calculations, the temperature of the CPU heatsink will be at -10 degrees C. This doesn't necessarily mean that the CPU itself will be that temperature, but it will be very close.

    What I'm looking for specifically is a datasheet or specification sheet of some type that states that a CPU will not be damaged at -10 degrees C, or a datasheet that gives an acceptable range of operating temperatures for a CPU. I absolutely need something that I can reference.


    Here's a link to some Intel CPU datasheets and thermal guidelines:
    http://www.intel.com/content/www/us/en/processors/core/CoreTechnicalResources.html
    Reply to Cobra27
  7. What you really have to pay attention to is condensation, if your temps go too low (below room temp) you are going to collect condensation, which is going to drip everywhere, making a super cold cpu useless for daily activities.
    Reply to HDmac
  8. Brett: Low temperature stress fractures, and stress fractures due to temperature fluctuation are what we're trying to avoid. Because we don't have any information regarding the actual layout of the CPU it's not really possible to do an independant analysis to determine whether or not fractures will be a problem.

    Cobra: Thanks for the link. Unfortunately, all that is shown in there is the minimum storage temperature. We may have to use that if I can't find any source.

    HDmac: We've solved the condensation issue already. I can't really go into detail, but it was a simple problem to fix.

    I'll be talking to a specification engineer from Intel tomorrow. If he gives me an actual number I'll post it here for anyone else who is curious or for anyone who may google this issue in the future. If anyone else has any solid leads I'd like to hear from them
    Reply to Enorminous
  9. It's a shame there was never an update on your project. Sounds very interesting.
    Reply to lukeebee
  10. Hi lukeebee,

    I'm sorry for forgetting to do an update! It's been some time, but I can let you know how it went. We did end up building a cooling device that worked quite well, but we had to change a few things around.

    We did some calculations for heat transfer, and found that adding insulation would prevent condensation from forming on the hose if we ran the system at -20C (-4F). Unfortunately, the heatsink would be so cold that condensation would form on the BACK of the motherboard as well. Again, we could insulate for that, but the amount of work necessary was much more than we initially thought. We were designing this so that somebody could install it on their computer as easily as a water cooling setup, so this problem forced us to look at alternatives. In addition, the amount of insulation required on the hose would have made it incompatible with most holes already available on computer cases, which was another mark against the -20C build.

    We decided to instead go with what we called a "dual-loop" setup. The dual-loop setup consisted of a water loop connected to a refrigeration loop. The water loop was similar to other water cooling setups on the market. We had a pump, a reservoir, and a CPU heatsink. This worked quite well, as it made our system compatible with any other custom CPU, GPU, or RAM heatsink on the market. It was exactly like hooking up a water cooling setup, except that our system was in its own box that sat beside the computer.

    We used a refrigeration system to cool the water. The water reservoir and refrigeration system sat inside the "cooling box". We designed a heat exchanger to transfer heat from the water reservoir into the refrigeration loop. We used a refrigeration compressor that we selected due to its quiet operation and small size. After testing the setup, we found that it was capable of cooling up to 600 Watts, based on the duty cycle of the compressor. This meant that it would have been very easy to connect a GPU heatsink in series with the CPU heatsink.

    We were still limited by condensation, but now we were also limited by the freezing point of water... Our refrigeration coils would hit -16C (-3.2F), so of course the water would freeze. Our solution to the condensation was to tune the system so that the compressor would maintain the temperature of the water slightly above the point where condensation would actually form (the dew point of the air). For a room with air at 20C (68F) and 50% relative humidity, this was about 9C (48.2F). This might not seem like a big improvement over water loops, but water loops have to run at temperatures that are hotter than the room they are in. If the room is 20C, the water loop may run at 30-40C. Our system was able to maintain the water at 9C very consistently.

    We solved the freezing issue by adding propylene glycol to the water reservoir. Propylene glycol (PG) is a "food safe" antifreeze. It's used in fog machines and e-cigs as well. The good think about it was that it was also "plastic-safe", meaning we could use it with the combination of materials that were present in our system without risking corrosion. The green colour of the PG also gave the water loop a really awesome look, especially as the fluid spun around our helical-shaped heat exchanger. I think we ended up using 40%PG and 60% water. We had some slight icing in our heat exchanger, but it didn't accumulate beyond the first bit and it didn't affect the performance overall.

    So how did it work? Very well. I can't remember the exact motherboard that we used. I think it was an ASUS Rampage. It was the expensive ASUS board that was available about three years ago. We ended up paying about $270 CAD for the board. We changed the overvoltage jumper on the motherboard to allow for the highest voltage possible, and proceeded to overclock an AMD 965 II Phenom X4 BE. I'm not a master at overclocking, unfortunately, but we were able to achieve some pretty respectable speeds. We almost beat the water cooling record posted on HWbot.org. Our limitation wasn't temperature, it was my inexperience at overclocking and possibly the affinity to overclocking that our specific CPU had. I've heard that some batches of CPUs are more overclock-able than other. Throughout all of this, the highest CPU temperature that we measured was 40C (104F).

    All in all, it was a very fun project that performed better than we had hoped. Unfortunately, the cost of the components and assembly was too high for the system to be considered marketable. It was ultra-enthusiast and would cost more than a dual-780 rig, even after factoring in favourable production and component costs.

    Feel free to ask any questions. As I found out today, I still get email alerts for this thread.
    Reply to Enorminous
  11. Just to ask, did you test it at at stock speed? Did the cooling itself provide any edge over consumer cooling solutions, in terms of performance?
    Reply to Convorus
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