Do not use the macbook pro '11 under clamshell mode! Proof inside!

[nnoob]

Did some experiment, I test it with wprime benchmark and monitored it with throttlestop for a few minutes.
The author of Throttlestop commented on this experiment: https://forums.macrumors.com/posts/13124402/
Here the result:

Open:


"clamshell mode":

 

[Nopstnz8]

So what are you trying to prove? Lower clock speed in clamshell mode?

 

[Apple 26.2]

I do it all the time... not a problem.

 

[stevenlangley1]

I'm not sure what I'm suppose to be seeing here.

 

[derickdub]

OP is just stating the obvious. Of course the CPU will get warmer, even at a lower multiplier. The keyboard helps dissipate a lot of the heat from the internals.

 

[Apple OC]

nothing to see here ... continue clam-shelling folks

 

[Macsavvytech]

OP is just stating the obvious. Of course the CPU will get warmer, even at a lower multiplier. The keyboard helps dissipate a lot of the heat from the internals.

Actually, no it doesn't its blocked off from the motherboard.

 

[derickdub]

I still really don't see the point in leaving the lid closed though. Once you 'wake' the computer up, the screen shouldn't come back on. At least mine doesn't with the exception of using a mini-DisplayPort -> DisplayPort cable. And that has only been a problem with mine and a few other MBPs AFAIK.

 

[Eddyisgreat]

Once you 'wake' the computer up, the screen shouldn't come back on.

except it does, on lion.

 

[derickdub]

Actually, no it doesn't its blocked off from the motherboard.

My keyboard gets warm about where the CPU sits on the logic board. I'm not saying that it's a design feature for the keyboard to vent heat, but of course there is much less resistance for the heat to leave the MBP when the lid isn't closed to insulate it.

except it does, on lion.

I didn't realize this, I haven't used clamshell since SL so...

 

[Macsavvytech]

My keyboard gets warm about where the CPU sits on the logic board. I'm not saying that it's a design feature for the keyboard to vent heat, but of course there is much less resistance for the heat to leave the MBP when the lid isn't closed to insulate it.

I think you misunderstood what I was saying, in terms of fans it is completely disconnected, heat can dissipate through the aluminium but the effect would be fairly minimal.

nothing to see here ... continue clam-shelling folks

This

 

[dsio]

My keyboard gets warm about where the CPU sits on the logic board. I'm not saying that it's a design feature for the keyboard to vent heat, but of course there is much less resistance for the heat to leave the MBP when the lid isn't closed to insulate it.

Your keyboard gets warm due to air from the vent at the back blowing over the aluminium as the screen hinge diverts its flow. Its actually not the aluminium dissipating heat, its the aluminium absorbing heat that would otherwise be vented into the air.

 

[dsio]

As far as this test goes, its about as about as scientific as "I say so, therefore it is".

What was the constant ambient temperature?

How many threads were you calculating primes on simultaneously?

What surface was the laptop running on and how far was it from any obstructions at the rear?

 

[derickdub]

Your keyboard gets warm due to air from the vent at the back blowing over the aluminium as the screen hinge diverts its flow. Its actually not the aluminium dissipating heat, its the aluminium absorbing heat that would otherwise be vented into the air.

If this were the case wouldn't the hinge and aluminum between the hinge and keyboard be warm too? Mine is still fairly cool where as my left half of my keyboard is obviously warmer.

Like Macsavvytech said though, the effect is fairly minimal and probably isn't worth the annoyance of the second monitor to some people. I also wasn't aware you couldn't open the lid with lion.

 

[dsio]

If this were the case wouldn't the hinge and aluminum between the hinge and keyboard be warm too? Mine is still fairly cool where as my left half of my keyboard is obviously warmer.

Like Macsavvytech said though, the effect is fairly minimal and probably isn't worth the annoyance of the second monitor to some people. I also wasn't aware you couldn't open the lid with lion.

Heat from the back will only be when its operating full tilt, some minor warmth from the keyboard under less load would be expected, there is a fair bit of effort that's gone into insulating everything from the logic board though.

 

[nnoob]

As far as this test goes, its about as about as scientific as "I say so, therefore it is".

What was the constant ambient temperature?

How many threads were you calculating primes on simultaneously?

What surface was the laptop running on and how far was it from any obstructions at the rear?

8 Threads
Flat nothing on the wooden desk except for the cables
It was ~80 degrees Fahrenheit or 27 degrees Celsius

 

[dsio]

8 Threads
Flat nothing on the wooden desk except for the cables
It was ~80 degrees Fahrenheit or 27 degrees Celsius

Would you mind posting a shot of that program with the CPU at idle as well as a base reference. In clamshell mode as well.

 

[nnoob]

Would you mind posting a shot of that program with the CPU at idle as well as a base reference. In clamshell mode as well.

sure, You should keep it open when you doing something cpu intensive.

 

[nnoob]

open:




clamshell: (It spikes more often in clamshell)

 

[karohan]

You're not the only one to post results like this. There have been others that have posted benchmarking results pointing to a performance decrease when in clamshell mode.

As a clamshell user in SL, I guess I can easily circumvent this by just opening the lid and keeping that screen off. However, I'm concerned for Lion, where apparently you can't keep the lid of the MBP open but still be in clamshell mode.

 

[wegster]

Your keyboard gets warm due to air from the vent at the back blowing over the aluminium as the screen hinge diverts its flow. Its actually not the aluminium dissipating heat, its the aluminium absorbing heat that would otherwise be vented into the air.

Can someone also confirm there's actually no air *intake* at all coming in via the keyboard?

The posted numbers aren't surprising, the CPU looks like it's temperature throttling itself, no? Even if the keyboard doesn't increase airflow, the upper body still likely has small amount of heat dissipation via airflow over it, versus closed in clamshell mode. Without taking samples of temps over time or ensuring enough cooldown to start at the same exact CPU temp in open vs clamshell mode, across multiple tests, it's not exactly conclusive, but seeing a difference of roughly 1*C or so isn't a real surprise.

Maybe I'm misunderstanding the data in the screenshots - look at the variance in the frequency multiplier in the second shot's open mode - with max temps of 65*C the multiplier is all over the place - doesn't seem to be exactly under load so much as possible sporadic in and out of boost from background processes, versus doing anything maxxing the CPU out.. ??

 

[nnoob]

You're not the only one to post results like this. There have been others that have posted benchmarking results pointing to a performance decrease when in clamshell mode.

As a clamshell user in SL, I guess I can easily circumvent this by just opening the lid and keeping that screen off. However, I'm concerned for Lion, where apparently you can't keep the lid of the MBP open but still be in clamshell mode.

i use switchresx for deactivating the lcd monitor it works fine in lion

 

[dsio]

Can someone also confirm there's actually no air *intake* at all coming in via the keyboard?

The posted numbers aren't surprising, the CPU looks like it's temperature throttling itself, no? Even if the keyboard doesn't increase airflow, the upper body still likely has small amount of heat dissipation via airflow over it, versus closed in clamshell mode. Without taking samples of temps over time or ensuring enough cooldown to start at the same exact CPU temp in open vs clamshell mode, across multiple tests, it's not exactly conclusive, but seeing a difference of roughly 1*C or so isn't a real surprise.

Maybe I'm misunderstanding the data in the screenshots - look at the variance in the frequency multiplier in the second shot's open mode - with max temps of 65*C the multiplier is all over the place - doesn't seem to be exactly under load so much as possible sporadic in and out of boost from background processes, versus doing anything maxxing the CPU out.. ??

The multipliers look wrong at every state in that Throttlestop program, looks like something slapped together in Visual Basic, so I wouldn't put a great amount of faith in it.

 

[Eddyisgreat]

Can someone also confirm there's actually no air *intake* at all coming in via the keyboard?

The posted numbers aren't surprising, the CPU looks like it's temperature throttling itself, no? Even if the keyboard doesn't increase airflow, the upper body still likely has small amount of heat dissipation via airflow over it, versus closed in clamshell mode. Without taking samples of temps over time or ensuring enough cooldown to start at the same exact CPU temp in open vs clamshell mode, across multiple tests, it's not exactly conclusive, but seeing a difference of roughly 1*C or so isn't a real surprise.

There is absolutely no air intake at all coming in via the keyboard.

I could go into a long winded discussion about heat pipes and heat sinks and airflow and fan design but I try to avoid doing so.

 

[deadwulfe]

nothing to see here ... continue clam-shelling folks

This. I also question if the OP waited long enough for all of the tempratures to go back to what they were prior to starting the first test or if they ran them back to back.

There is absolutely no air intake at all coming in via the keyboard.

I could go into a long winded discussion about heat pipes and heat sinks and airflow and fan design but I try to avoid doing so.

You could sum it up with the fact that there is a solid wall of material between the keyboard and the rest of the computer, preventing any airflow through the keyboard myths from being logical.