Sidebar Sidebar
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

Is it bad to keep your clam shell shut while using an external display?

R

ReidStylez

macrumors member
Original poster
Jul 11, 2010
63
3
From what I know the air intake is through they keys and the exhaust is just before the screen which when it's closed it closes off most of the air flow and blows the exhaust into the screen.

I see pictures of people with theirs shut all the time and always wondered if this was a bad thing to do or not.
 
You'll have no issues at all by leaving it shut and using an external display. It will ventilate just fine and work for years to come like this. Enjoy. :)
 
from what I gather, it is not a hard thing to do. It can cause your MBP to run at a slightly higher temperature, but you should be okay.
 
ReidStylez said:
From what I know the air intake is through they keys and the exhaust is just before the screen which when it's closed it closes off most of the air flow and blows the exhaust into the screen.

I see pictures of people with theirs shut all the time and always wondered if this was a bad thing to do or not.
Click to expand...
There is no problem using your Mac in clamshell mode. There is no air venting at all through the keyboard. All venting is through the vents located at the rear, near the hinge.
 
I would think it's ok because Apple sells the stand that keeps it shut. I don't see Apple selling something for their products that harms it.
 
derbothaus said:
Wonder why every user that does this has keyboard imprint on their display if ventilation and heat are not a factor? Prior to glass it was a bad idea.
Click to expand...
Heat radiates in all directions. That doesn't mean heat is vented in all directions. Heat radiates to the enclosure base, too, but that doesn't mean it's used for venting, either. The keyboard has a solid sheet under it, preventing any meaningful airflow. It's not a bad idea to run in clamshell mode, even without a glass display. I've never had any issue running in clamshell on an Early 2008 MBP with matte display, which isn't glass.
 
GGJstudios said:
Heat radiates in all directions. That doesn't mean heat is vented in all directions. Heat radiates to the enclosure base, too, but that doesn't mean it's used for venting, either. The keyboard has a solid sheet under it, preventing any meaningful airflow. It's not a bad idea to run in clamshell mode, even without a glass display. I've never had any issue running in clamshell on an Early 2008 MBP with matte display, which isn't glass.
Click to expand...

In my past experience, running games under bootcamp, keeping clamshell closed was a bad idea, it led to machine hanging, presumably due to overheating, was fine when open.
 
iMacDragon said:
In my past experience, running games under bootcamp, keeping clamshell closed was a bad idea, it led to machine hanging, presumably due to overheating, was fine when open.
Click to expand...
It won't hang due to overheating; it will shut down. The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat (around 100C/212F - 105C/221F, depending on your processor).
 
GGJstudios said:
It won't hang due to overheating; it will shut down. The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat (around 100C/212F - 105C/221F, depending on your processor).
Click to expand...

I think it was the graphics chip overheating, not the cpu.
 
iMacDragon said:
I think it was the graphics chip overheating, not the cpu.
Click to expand...
It won't overheat due to being in clamshell mode. Apple notebooks are designed to run in clamshell mode and do not depend on the lid being open to maintain safe operating temperatures.
 
GGJstudios said:
It won't overheat due to being in clamshell mode. Apple notebooks are designed to run in clamshell mode and do not depend on the lid being open to maintain safe operating temperatures.
Click to expand...

I know they say that, And for non intensive purposes they seem to cope fine, but having display open definitely does lower temperatures by a notable degree as it allows more heat radiation into non trapped air, with screen down, less heat can escape via upper surface, and I suspect that less heat escapes via the hinge too as half potential area for airflow is near enough closed off by the screen being down.

It did the lockup on me more than once, and only when lid was closed. This was on a late 2008 unibody. Never had a problem with lid open.
 
GGJstudios said:
It won't change temps to any significant degree. Use iStat Pro to track your actual temps in open and closed mode. The temps will not change significantly enough to cause any problems.
Click to expand...

There was a huge difference in fan speed ( and thus efficiency in cooling ) for me, in both cases temps maxed out at similar values, but it was clearly struggling harder to keep it cool with lid closed.

you need to monitor both fan speeds and length of time spun up and temperature for full picture.
 
iMacDragon said:
There was a huge difference in fan speed ( and thus efficiency in cooling ) for me, in both cases temps maxed out at similar values, but it was clearly struggling harder to keep it cool with lid closed.

you need to monitor both fan speeds and length of time spun up and temperature for full picture.
Click to expand...
Apple notebooks do not depend on the lid being opened to maintain safe operating temperatures. If that were not true, Apple would not give instructions on how to operate in clamshell mode. It is simply false and misleading to suggest otherwise.
 
GGJstudios said:
Apple notebooks do not depend on the lid being opened to maintain safe operating temperatures. If that were not true, Apple would not give instructions on how to operate in clamshell mode. It is simply false and misleading to suggest otherwise.
Click to expand...

I'm not saying don't do it, just saying it will run hotter, or at least, less efficiently. This may be perfectly acceptable, and in majority of cases, probably works just fine. I haven't managed to get my 2011 model to lockup under any form of stress, at least after the first couple of updates that fixed an issue with this on OS X ( never had an issue on windows, I tortured it with prime95+furmark for an hour to test how thermal management coped. end result was cpu clocking itself down and bouncing around 1.1-1.3ghz to keep within thermal profile, but no lockups. I suspect this would happen faster/more often with lid closed, but I didn't actually test this ), but I still like to keep the lid open even when using in 'clamshell' mode, as the fans do spin up less, so it's quiter.
 
They used to actually say to never do this. Recently (last 5 years) they put the KB together about it. I'll try to find a source for this, it was either late G4's or first Core Duo books.
They do get hotter and they do run the fans quite a bit more. Whether or not damage can occur is debatable but any extra heat wears the components out more quickly, not debatable. Proc, GPU and battery are at risk.
Apple designed the fans to only start revving very late to minimize noise for a better "experience". Mac laptops are not renowned for their thermal dispersion anyway so having core2 or i7 processors idle at 72ºC is not acceptable with the lid shut. And considering PC counterparts stay well within 40-50º range on official heatsinks, same model proc. (I am aware that the space limitations due to the seriously thin Macbook Pro design play a great part in the extra heat)
I just don't care to add any more. I tell my users the same. The ones that do it tend to have smudgy keyboards half printed in grease on the display. Coincidence?
 
Last edited:
You must log in or register to reply here.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.
Top Bottom
Back