CPU Temp. and Fan Control

OnceYouGoMac · Mar 11, 2010

Hi gang,
Without debating the acceptable heat range of a Mac, or the glitches of this or that lol, I have just a simple question that, if you would answer, would make me very happy and thankful. I have one of the new unibody white Macbooks (which I love btw). So, I use the program Temperature Monitor. At night, I run three highly processor-and-resource intensive applications, so that the Activity Monitor shows both cores at 100% for 8 or 9 hours straight, and the RAM is mostly wired. But, according to Temperature Monitor, the CPU temperature, in Fahrenheit, stays at a consistent 215F! The fan kicks on once in a while and gets it back down to 198F or so, but I am concerned about such high temps going for 9 hours at a time. I know Apple assures me this is normal, but just a basic knowledge of physics and thermodynamics tells me that a temperature that could boil water radiating out to all my parts for that long must be shortening the life of something somewhere lol. So, I got SMC fan control. I only use it in that one particular situation, and it definitely cools the CPU cores off to a much more reasonable level. So here is what I want to know:

cms fan control has an option to display the temperature, just like Temperatue Monitor does. I would like to just have one program doing that. In your OPINION and EXPERIENCE and any FACTS you know, is the reading from Temperature Monitor, or on CMS Fan Control, more accurate? Not trying to start a war, just wanted some basic information. Thank you! Merci!

vansmith · Mar 11, 2010

I don't know enough about electronics to comment on the continued exposure of heat to computer parts but what could you possibly be doing for 9 hours straight on a notebook that is that processor intensive? If you really have to do that every day, you should be looking at some other solutions.

DarkestRitual · Mar 11, 2010

WOW. That's too hot. Anything over 100 C (212F) should make you worry, because that will boil water...

Get a can of compressed air and please, blow that sucker out! Get a cooling pad!

I also use iStat menus. Pretty sweet, customizable UI.

OnceYouGoMac · Mar 11, 2010

Thanks for the thoughts. However, I was asking just one question: is SMCFanControl or Temperature Monitor more precise in its readings? Thanks.

DarkestRitual · Mar 11, 2010

Probably SMC, but I'll leave that to the experts

Nethfel · Mar 11, 2010

The Penryn CPU can go as high as 105c TCase (thermal reading at the case), but it shouldn't stay there really for any length of time. Your sitting at about 101c, which to me is a bit high for a system with proper cooling - but I'm used to the aluminum model which will stay at 90-91c at 100% usage with the fan going. What seems a bit weird to me is that your fan isn't staying on all the time with 100% usage on both cores - I know mine did.

In terms of which is more accurate - I can't answer that - I know that many times programs that supposedly read the temperatures from the same registers can report different values (sometimes it may just be because of the timing of the reads of the data itself can be different causing a difference in values) but if the two display within a couple of degrees of each other, I wouldn't worry about getting all technical about which is more accurate. If there is a huge difference then I'd be concerned.

IMHO - First do a comparison to see how far off the two temps are. If they are far off, I'd probably rather the one that is reporting high to use for figuring what to set SMC Fan Control to kick the fans on at. If Temp Monitor is showing the cpu at 100c and SMC Fan is showing at 91c then I'd probably use Temp Monitor as my guide at least for how I configured SMC.

Also: Onceyougomac: could you possibly correct your system info: Macbook Unibody 2.6 Dual, 2GB RAM, 250 GB HDD - I've checked all of the Macbook models, and none of them (outside of the pro line) offer a dual core 2.6GHz CPU - it makes it hard to figure exactly which system you have for questions like this to find the proper CPU version as different mobile CPUs can have VERY different max temp values (ie: <90c to >100c and which you have is important when determining what the max safe temp is).

DarkestRitual · Mar 11, 2010

If it's the white unibody, it's the white 2.26 would be my guess, and he just missed a 2.

Nethfel · Mar 11, 2010

DarkestRitual said:
If it's the white unibody, it's the white 2.26 would be my guess, and he just missed a 2.

You're prolly right *but* I try to not assume too much

OnceYouGoMac · Mar 11, 2010

Nethfel said:
The Penryn CPU can go as high as 105c TCase (thermal reading at the case), but it shouldn't stay there really for any length of time. Your sitting at about 101c, which to me is a bit high for a system with proper cooling - but I'm used to the aluminum model which will stay at 90-91c at 100% usage with the fan going. What seems a bit weird to me is that your fan isn't staying on all the time with 100% usage on both cores - I know mine did.

In terms of which is more accurate - I can't answer that - I know that many times programs that supposedly read the temperatures from the same registers can report different values (sometimes it may just be because of the timing of the reads of the data itself can be different causing a difference in values) but if the two display within a couple of degrees of each other, I wouldn't worry about getting all technical about which is more accurate. If there is a huge difference then I'd be concerned.

IMHO - First do a comparison to see how far off the two temps are. If they are far off, I'd probably rather the one that is reporting high to use for figuring what to set SMC Fan Control to kick the fans on at. If Temp Monitor is showing the cpu at 100c and SMC Fan is showing at 91c then I'd probably use Temp Monitor as my guide at least for how I configured SMC.

Also: Onceyougomac: could you possibly correct your system info: Macbook Unibody 2.6 Dual, 2GB RAM, 250 GB HDD - I've checked all of the Macbook models, and none of them (outside of the pro line) offer a dual core 2.6GHz CPU - it makes it hard to figure exactly which system you have for questions like this to find the proper CPU version as different mobile CPUs can have VERY different max temp values (ie: <90c to >100c and which you have is important when determining what the max safe temp is).

Oops sorry! Fixed.

OnceYouGoMac · Mar 11, 2010

So, no one knows exactly which temp monitor each program goes to, or which is considered more accurate? I cannot find this info anywhere.

Nethfel · Mar 11, 2010

Does it matter? Choose whichever one is reporting highest and use its temp offset (if SMC is reporting lower then the other reader) to determine what to set SMC to turn the fans on at and you'll be safe. You haven't even mentioned whether the two are really reporting different numbers...

vansmith · Mar 11, 2010

I know this isn't what you're looking for but you still haven't addressed my earlier question which I think could be helpful. If we know what it is you're trying to do, we may be able to provide some alternatives/solutions which would relieve you from having to even consider this an issue.

TattooedMac · Mar 11, 2010

Well my SMC has the same reading - + 1degree as the iStat shows. I use the SMC to monitor temp since i dl it and really dont need to look @ iStat anymore.
I know its not the comparison you are looking for but what im trying to get out is IMO i think SMC is pretty well accurate

Cheers

chas_m · Mar 11, 2010

All temperature monitors pull their info from the same place -- the temperature sensors of the Mac itself -- so they should all be within a degree of each other (and only that due to rounding generalisations).

And I agree with vansmith -- this is a CONSUMER computer you are taxing, and regardless of using fan control software to try and keep it a bit cooler, you are KILLING THAT THING by maxing it out so constantly.

Ever been in a server room? Those machines are built using parts of MUCH higher life rating than anything used in consumer computers, and they have to be kept at refrigerator-like levels of temperature in order to work reliably.

If *any* consumer computer could take that kind of abuse, it's likely to be Apple, but you know it just *wasn't designed* to be misused in that fashion. I think you can reliably count on having to replace that machine sooner than most of us.

DarkestRitual · Mar 12, 2010

And somebody named after an airport extreme base station code that they found within range of their local wireless is definitely a troll.

technologist · Mar 12, 2010

Besides revving up the fans, is there anything else you can do to help it radiate heat? First, make sure the room is within the allowed operating temperatures for the system (see your manual.) If possible, the room should be climate controlled. Also, make sure there's good airflow around the machine (place it on a flat, solid surface with no papers or other items up against it.) Also consider a cooling pad or wire oven rack to elevate it off of the desk. Wearing out the fans could be as expensive, ultimately, as running it at high temperature.

OnceYouGoMac · Mar 12, 2010

1. To the guy who said I was a troll, I can assure you that I am nothing more than a new Mac user who loves my Mac and wants to learn more about it. I do not appreciate being called a troll.

2. Do those laptop cooling pads that you put laptops on really work? To me, it seems they would only cool off the bottom plastic, and not the internal components.

3. I keep my apartment very cool, so ambient temperature is good.

4. One reason I got a Mac is the reputation for running stably for long periods of time under all sorts of conditions. I am confident my Mac can handle what I need it to, but I was thinking, if my fan broke because of heavy use, isn it not a pretty simple matter to re-install a new fan? I have done it dozens of times on my old Windows machines, and I assume it is just as easy on a Mac?

5. Finally, French is my native language, so if I ever say anything that sounds odd, offensive, trolling, etc., it is probably just a language barrier, so please talk to me privately first and we can probably clear it up.

Thanks all!

DarkestRitual · Mar 12, 2010

1. I didn't say you were a troll, I said the guy named after an Airport Base station was. The one who said, "Macs are the best computers. They don't ever get hot." Then again, if you'd read a username with a comment, you'd have seen that I had already replied to you and was referencing the post above mine (which was deleted by the mod after I reported it), and then you wouldn't have gotten your feathers ruffled. Of course, it would have helped had dtravis7 deleted MY post as well, but what can ya do.

2. The laws of physics would dictate that by cooling off the bottom plastic, you will cool off the overall temperature of the machine. It's called heat conduction. That's when it dissipates over material that is in direct contact. The convection cools the bottom of the PC, also allows more airflow to get into circulation, and then everything else cools off.

3. I don't know how your apartment manages to stay cool when you have a 215 degree computer sitting in it for 8-9 hours at a go.

4. Even my G5 Power Mac didn't make it through 5 years of no ventilation and constant smoking. Your little plastic macbook is begging you to stop treating it as server grade hardware. It's like forcing factory labor on a 6 year old child.

5. I had no problem with you or language barriers. I've got friends from all over the world with varying degrees of skill in the English language. I can work around that, easily.

chas_m · Mar 12, 2010

OnceYouGoMac said:
4. One reason I got a Mac is the reputation for running stably for long periods of time under all sorts of conditions. I am confident my Mac can handle what I need it to, but I was thinking, if my fan broke because of heavy use, isn it not a pretty simple matter to re-install a new fan? I have done it dozens of times on my old Windows machines, and I assume it is just as easy on a Mac?

It's probably NOT a simple matter for a variety of reasons:

1. IME taking machines apart, MacBooks aren't as bad as G4 iBooks (shudder), but neither are they a cakewalk. Lots of easily-damaged pieces and wires that must be carefully disconnected. Laptops are an order of magnitude more crammed than desktops.

2. Like a lot of things inside a Mac, the fans are custom-shaped/designed and also made to work with the (also Apple-designed) temp sensors. So you generally can't just go down to Bob's Spare Parts store and plunk in any old fan. I haven't worked on the latest MacBooks so things could have changed, but generally speaking these are parts only AASPs can replace. It's just like how your car has parts that anybody manufacturers, but the crucial parts are generally only made by (and can only be ordered from) the manufacturer by the dealers.

PS. The fact that you have needed to replace the fans "dozens of times" on your Windows machines makes me even more fearful for the lifespan of this Mac.

You may want to re-read DarkestRitual's point #4.

OnceYouGoMac · Mar 12, 2010

Ok thanks my friends lol...sorry I misunderstood the troll comment. I will try to ease up on the fan full speed use.

CPU Temp. and Fan Control

OnceYouGoMac

vansmith

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DarkestRitual

OnceYouGoMac

DarkestRitual

Nethfel

DarkestRitual

Nethfel

OnceYouGoMac

OnceYouGoMac

Nethfel

vansmith

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TattooedMac

chas_m

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DarkestRitual

technologist

OnceYouGoMac

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chas_m

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