15C with air cooling?

C

ChingChang

Supreme [H]ardness
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Someone on my floor claims to get like 15C with air cooling. I'm just wondering if he's BSing or this is possible.

He's using one of those big Asus cases with an antec PSU. Don't think he has any other case fans in it. His processor is a Pentium D I think. If not, it's a 3ghz Penitum 4. Not sure exactly which processor. And his HSF is this one. I don't know how good they are, but I've never seen anyone recommending it.

The other day he showed us his temp monitor (the one that came with his asus board) displaying like 20C. I don't believe it though. I just don't see how anyone can get a high end dekstop Intel processor down to room temperature on air cooling with a cheap HSF.
 
Possible? Probably. I don't buy it though. From experience with many different processors, lots of different air cooling, and several after-market HSF's, about the lowest I have seen on an AlthonXP, Athlon64, Pentium 4, Pentium D, etc is 30-35C with air. It's entirely possible he is not lieing though, as his mtoherboard could be way off and reporting that tempature, and he simply may not know any better as to how unrealistic that is.
 
His room must be pretty cold or something. I have a P4 3.2 ghz with a Thermaltake Spark 7+ heatsink with a vantec tornado on it on low more often than not and it idles at about 23C most of the time. But also, my room is always very cold, so thats a big factor, and it might be the same for the other person.
 
It's probably a bunch of BS. 15C is 59 degrees F, and 20C = 68F. Both of those are below normal comfortable air temps in people's homes (most people like 72-75F). If he doesn't wear a jacket around the house, I wouldn't believe it. Air won't cool below ambient temperature.
 
The temp sensor must be busted, or hes full of shit. You cannot achieve sub-ambient temps with air, so... yeah. I seriously doubt his room temp is 15C, either.
 
Judging by "on my floor" I am assuming you are in a dorm? I will also assume then that because 99.8% of all dorms lack airconditioning, and that no place in New Jersey is currently below 59F (15C) that it is definitely bull shit that he gets 15C temps. It is physically impossible with that cooler to get lower than ambient temperatures. The best you will do is a few degrees above ambient. He most likely has a faulty sensor, motherboard thermistors generally are very poor and have specified ranges of +/- 5C at best.
 
If it's -15C in there, I could see a temp like that. Otherwise I'd suspect the temp sensor. I have a MSI 865PE based motherboard in one of my computers and programs always read the temp as being in the 3C to -4C range depending on air temp.
 
Decker87 said:
What is the best method for getting accurate temps?
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A real temperature probe attached to the bottom of the heatsink as close as you can get it to the processor without getting between the processor and the heatsink.
 
Erasmus354 said:
Judging by "on my floor" I am assuming you are in a dorm? I will also assume then that because 99.8% of all dorms lack airconditioning.../snip
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We do have universities down here in the south where its hot too... ;) Most dorms are air conditioned here. But you can't get your rooms down that cold anyways. Chances are his temp sensor is waaaaaay off or he's full of crap. Considering that the processor is generating a significant amount of heat, no matter how efficient the cooler is it would have to be significantly colder in the room to get those temps.

But the OP is in NJ so you know better about dorms there than me. :D
 
Ok, lets do some simple physics:

You can't get below ambient temp period. Not even with water. Unless it involves phase change like the bong cooler. I'm not referring to vapos, I mean real "phase change". So unless ambient is a cool 15C, and the cooling system is capable of achieving ambient temps (extremely unlikely, unless there's a couple hundred CFM), it's impossible.

Now the exception to this is going to be the following:
devices such as peltiers, or freon loops. These are the most common two used, and to my knowledge, the only ones I've ever seen used on a computer, besides the bong cooler, to achieve sub ambient temps. Liquid nitrogen doesn't count. Everything from a lab chiller used to chill water, to a vapochill uses freon.

BTW, trust what you know to be true, not equipment. IE, even if a calculator says 4x5=40, it is still wrong. Just like if a sensor says the temp is 15C, and ambient is 20C.
 
I agree with mikelz, this guy is feeding you some serious sh*t, whether he knows it or not. You said he has an ASUS case, good chance he has an ASUS mobo which are well-known for incorrect temp readings.
 
Unless he dug a 1000ft deep hole, put the computer down there, got himself some sort of air extraction system, then air cool it...AT NIGHT...
Wait, put the computer in a freezer but use air coolers? technically, the computer itself is being aircooled albeit in a freezer
 
Actually I'm up in Rochester NY (RIT), and we have air conditioning. But it doesn't get too cold from the AC unless you're sitting on it. My temps here are the same as they were in NJ though, so it's not like the room temperature is what's giving him such low temps.

I figured it was his motherboard also. He is using an Asus board (he's the biggest intel/asus/microsoft fan boy ever). I never knew Asus had a bad reputation for faulty sensors, but my Asus A7N8X Deluxe's sensors are screwed up. The CPU temps are displayed as MB temps, and MB is shown as CPU :p
 
My comp temps on my 3.2c average 30 *C idle and case temps are around 18*c -23*c so I really doubt its 15 and its 60 degrees here...
 
mikelz85 said:
Ok, lets do some simple physics:

You can't get below ambient temp period. Not even with water. Unless it involves phase change like the bong cooler. I'm not referring to vapos, I mean real "phase change". So unless ambient is a cool 15C, and the cooling system is capable of achieving ambient temps (extremely unlikely, unless there's a couple hundred CFM), it's impossible.

Now the exception to this is going to be the following:
devices such as peltiers, or freon loops. These are the most common two used, and to my knowledge, the only ones I've ever seen used on a computer, besides the bong cooler, to achieve sub ambient temps. Liquid nitrogen doesn't count. Everything from a lab chiller used to chill water, to a vapochill uses freon.

BTW, trust what you know to be true, not equipment. IE, even if a calculator says 4x5=40, it is still wrong. Just like if a sensor says the temp is 15C, and ambient is 20C.
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Why can't you get below ambient temps with water cooling? Just wondering.
 
Water cooling basically uses water to cool the CPU, and air to cool the water (radiator)...the water would have to start out below room temp.
 
ChingChang said:
Why can't you get below ambient temps with water cooling? Just wondering.
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Any type of cooling system is just transferring heat, so whatever the final medium is (99% of the time: air) is going to be the absolute minimum temperature achievable by non-phase-changing means.

In reference to the refrigerator comment, refrigerators use phase-change to cool the air, so it still doesn't count :)
 
ChingChang said:
Someone on my floor claims to get like 15C with air cooling. I'm just wondering if he's BSing or this is possible.
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sure its possible, with a great enough temperature differential
but considering there is some ineffciency in transfer hed need to be employing some pretty cold air and lots of it


addressing the 1% of the time your not transfering the final stage to air
if your next to a cold lake, if you can dump it into a well or underground

and the another possibility other than "typical" phase change (where everyone thinks AC)
is evaporative cooling as mentioned above

latent heat of vaporization or enthalpy of vaporization
http://www.physchem.co.za/Heat/Latent.htm
http://www.physlink.com/Education/AskExperts/ae396.cfm
 
Maybe the guy has a peltier?

ChingChang said:
Why can't you get below ambient temps with water cooling? Just wondering.
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For the same reason why when you set your beer out on the table, it doesnt get any colder than room temp.
 
bob said:
Maybe the guy has a peltier?
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You would need an AMAZING heatsink to dissapate all that heat. You need a mighty powerful watercooling setup to cool a peltier, even...
 
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