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Max safe temp for i7 and Core2Duo

C

Cubytus

macrumors 65816
Original poster
Mar 2, 2007
1,444
25
Hi there,

this question is pretty simple. I have a 2009 pre-unibody MacBook that has a Core2Duo inside, and it's making a *lot* of noise. Actually, the fan is running full blast, and we all know how annoying this small fan can be at 6200rpm.

Strange is that the CPU isn't loaded to any extent (about 15% right now), and reported temp (from iStat Nano) hovers around 58 degrees. Ambient temp is a rather cool 20 degrees, and AFAIK internal fins have been cleaned, however running with fan full on for extended periods of time surely clogs it faster than usual. In fact, by reducing fan speed to about 4200rpm, temp only climbs to 61 degrees. I'll check the fins again when I find some time.

My question is, what's the max safe temperature for a C2D to operate at? I know it has an auto-throttle mechanism to avoid damaging itself while running hot, but of course I's like to avoid hitting that wall if I were to use a fan control software. Would a higher temp in any other part be responsible for this fan speed increase?

By comparison, my current MBP has an i7 inside that maxes out fan only when reaching 80 degrees. I empirically determined the machine starts to act erratically when CPU reaches 90 degrees.
 
Do you clean the heat sink regularly? If not, open up your Mac and perform some cleaning. Get rid of all that dust that might be causing extra temps. Do you have the exhaust vent covered? This will rev up the fan in order to move a higher air flow.

Core 2 Duos have a max temp of 105*C.
 
Honestly, no, I don't clean it very often. Last time was when I opened it to add more RAM, half a year ago. The vents are not covered in any way, although I do leave some papers on top of the built-in keyboard (I use the wireless one). Do I need to dismantle the MacBook to clean it properly? Or would a plain, canned air blast be enough? Or, would I benefit in some way to completely re-seat the heatsink after proper thermal goo removal and re-application?

105 degrees seems very high. I guess it's the temperature it can sustain before damage occurs, but wouldn't it throttle back before reaching this point?
 
105*C is a thermal limit for operation, but it isn't the temperature that will cause damage. Remember, these CPUs are soldered onto the logic board, process which submits a CPU to 217*C minimum to achieve liquefaction of lead-free solder.

Cleaning the heat sink can easily be done with a can of compressed air.
 
Sure but they don't sustain such a high temp while operating! I was referring to damage on the case and other components. And the soldering process itself is brief. So right for the compressed air, but do I need to dismantle the machine?
 
Huh, that's impossible without taking it apart entirely. This is a pre-unibody MacBook…
 
Well I could ask the question a little differently: what is considered a "normal" temp for a C2D loaded at 15%, installed in a pre-unibody MacBook and rather cool ambient temp?
 
Cubytus said:
Well I could ask the question a little differently: what is considered a "normal" temp for a C2D loaded at 15%, installed in a pre-unibody MacBook and rather cool ambient temp?
Click to expand...
Your temps are normal. If you're not already doing so, use iStat Pro (free) or iStat Menus ($16) to get accurate readings of your temps, fan speeds, etc., rather than relying on your sense of touch or sound. A forum member has posted a copy of iStat Pro that has been "tweaked" to enhance compatibility with Mountain Lion. You can download it here.
​
The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C (221F), GPU Tjmax = 100C (212F) on i3, i5, i7 processors. (Source: Intel)
​
Unless there is a rare defect in a Mac, most temps are well within the normal operating range, considering the workload being put on it. Websites with Flash content, games and other multimedia apps will put higher demand on the CPU/GPU, generating more heat. This is normal. If you're constantly putting high demands on your system, such as gaming or other multimedia tasks, expect temps to rise and fans to spin up accordingly. It's just your Mac doing its job to maintain temps within the normal range.
​
It is also quite normal for your Mac to become extremely hot to the touch during intensive operations. The aluminum body transfers heat more effectively than other materials used in computer casings, so you will feel the heat more. This doesn't indicate that it's overheating and will not harm the computer to be hot to the touch.
The bottom of your Mac notebook may become very warm during normal use. If your notebook is on your lap and gets uncomfortably warm, move it to a stable work surface that allows for good ventilation.
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Your fans are always on when your Mac is on, spinning at a minimum of 2000 rpm (for MBPs) or 1800 rpm (for MBAs, MBs and minis), or 1200 for the newest MBAs. Older iMacs have 3 fans with minimum speeds in the 800-1200 range, while the newest iMacs have a single fan, spinning at a minimum of about 1400 rpm. They will spin faster as needed to keep temps at a safe level. If your fans are spinning up without increased heat, try resetting the SMC. (PRAM/NVRAM has nothing to do with these issues, so resetting it will not help.)
​
The intake and exhaust vents are in the back of the computer near the hinge on all notebooks in the MacBook line (except the new MBP with retina display, which has intake vents along the sides at the bottom). The iMac vent is a slot on the back near the top of the computer. Make sure the vents remain unblocked to allow your computer to perform at its best. For Flash-related issues:
 
This info is really detailed, but mostly irrelevant to the topic on hand. The machine doesn't feel warm, there is no web browser opened, no aluminum body, iStat Nano is quite the same as iStat Pro, etc., and in fact, CPU has very few usage.
 
Cubytus said:
This info is really detailed, but mostly irrelevant to the topic on hand. The machine doesn't feel warm, there is no web browser opened, no aluminum body, iStat Nano is quite the same as iStat Pro, etc., and in fact, CPU has very few usage.
Click to expand...

15% usage on a c2d pre-unibody nets me about 60-65c with the fans speeding up slightly.
 
Cubytus said:
This info is really detailed, but mostly irrelevant to the topic on hand. The machine doesn't feel warm, there is no web browser opened, no aluminum body, iStat Nano is quite the same as iStat Pro, etc., and in fact, CPU has very few usage.
Click to expand...

Actually, quite a lot of that info is relevant, and is designed to answer not only questions already asked, but also anticipate future questions that may be posed by you or other readers. It stated the max temps and conditions related to them. Also, since your temps aren't extremely high but your fans are spinning faster, did you try resetting the SMC, as suggested?
 
GGJstudios said:
Also, since your temps aren't extremely high but your fans are spinning faster, did you try resetting the SMC, as suggested?
Click to expand...
Not yet, I'll try when I get back home.

Well the Apple support page don't list the operating temps for the CPUs, only environmental ones.
 
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