For the purposes of “operating” vs. “storage” temperature as shown in the manual?
I ask because the two ranges given for operating temperature and storage temperature for my particular Macbook Pro are VERY different, and mine was asleep when I unexpectedly spent almost two hours standing around in very cold temps.
Thanks!
In terms of physical factors like temp range, etc, you can safely assume that a sleeping laptop is not operating.
Moved to General Questions from Great Debates.
Why? Are certain electrical components less prone to damage from the cold than others? There’s still low-level processing going on in a sleeping laptop, so what makes that safer than the regular laptop processing?
What is happening under the hood?
The exact changes vary from system to system, but generally, the CPU is turned off or put in a very low-power state while RAM still keeps getting power. This means that little to no processing is done, but the current state of the system is saved for a quick recovery once the system is awoken again.
And by “very little processing”, I mean that some systems might maintain some very basic functions (like keyboard/mouse awareness, minimal network awareness, LED lights, USB charging, etc.) to make life easier for the user.
In terms of the OP’s question, however, the answer depends on how temperature affects circuitry. I’m afraid I don’t know.
And if you really want the nitty-gritty, you can download the ACPI specification (a standard dictating how computers should deal with power) and look at section 16, “Waking and Sleeping”.
(God help you if you do.)
Holy crap, I put this in GD? :eek: Sorry! I have no idea how I did that! 
Anyway, I’d still love answers from those who can put this kinda stuff into layman’s terms.
Other things I wonder: would the answer to my question differ if I had a Windows-based PC laptop instead of a Mac? Also, one of the reasons I asked is because the previously mentioned manual has 50 degrees F as the lower limit for “operating temperature.” I know this thing isn’t gonna blow up if I use it at 49, but how much leeway do I have?
The thermally critical bits of a portable computer are the silicon (band gap is temperature dependent) and the battery - if the battery is too cold, electrolyte movement is reduced and power delivery impacted - it may not be able to deliver enough current at all causing overload damage, battery life is lower, and there could be permanent damage (through crystal formation due to the reduced electrolyte flow). The LCD response time does slow down in the cold, too, but the backlight warms it up pretty quickly.
When a laptop is in a sleep state (as opposed to hibernate), power is being used to refresh memory and manage interrupts (for waking the device). This has two effects - the live circuitry is warm due to power dissipation (memory, memory controller and parts of the CPU), and the battery is warm due to current drain (you can only sleep a laptop for maybe 24 hours - they usually shift to hibernate at some point). So a sleeping laptop will maintain operating temp even if exposed to pretty cold conditions, especially if it is in a laptop case or bag. A laptop that has shifted to hibernate is off, and storage thermal limits apply.
The other issue to be aware of is allowing the laptop to come up to temperature after it has got really cold, to avoid condensation on cold parts causing water damage when power is applied.
Si
The upper operating limit is determined by the ability to take heat away from the processor IC. If its already 120 in the shade, you lap is going to be burned, ad your processor IC life will be reduced.
The lower limits are discussed by si_blakely upthread.
Another issue is the rotating memory. Differential thermal expansion/contraction limits the operating temperature range. There is thermal lag, so the laptop should be allowed to warm slowly to well within the operating temperature range before use. This will also take care of condensation caused by bringing a cold device into a warm, relatively humid atmosphere.
Another difference is the actual functionality of the machine. Components use various protocols to communicate between themselves. There are temperature specs for that communication to work properly. If you are in extreme cold, you may or may not damage something, but you might just have a transient failure.
-D/a
Actually, one question that this brought up: is the operating/storage temperature something that applies to the computer itself, or to the ambient room temperature around it? Or both?
I had always thought it was the latter. Am I wrong?
Your hard drive is probably also sensitive to cold temperatures. I suspect that it contains lubricants that would increase in viscosity at cold temperatures, and various critical bits might undergo different rates of thermal contraction that would interfere with the precision needed to read the discs. Of course the disc isn’t running when the machine is asleep, but I’d let it come back up to room temperature before I woke up the machine.
Sorry to bump, but I was curious about the question I asked two posts up. Basically, I’m always unsure how to treat stuff like the operating temperatures in the manual, which is why I was concerned about this whole thing to begin with. I just want to make sure I’m not doing anything harmful here by not having the room above 50 degrees when I’m net surfin’. 