Why does lion run so hot?!!

darkmast3r

Active Member
I have a macbook pro 13, mid 2009 and working well.
I've been using istat menu's to monitor the temperature of my cpu.
With lion installed it idles at around 55º, with web browsing it goes up to around 65/68º.
I have re-installed snow leopard and now my idle temp is around 40º, with web browsing around 48/50º which is a big jump from the lion temps.
Lion was installed from an upgrade but I did do a clean install too with the only program installed being istat menu's.
Does anyone else have this problem or have a solution to this as I do like lion but am worried it's going to shorten the life of my macbook?
 

CamFire

Distinguished Member
Open up ActivityMonitor and see what processes are consuming CPU activities the most. You will have to view all processes and sort on the CPU column.
 

NewBeetle

Distinguished Member
65-68 is fine, why worry? I can't remember the last time I heard of someone burning out a CPU in modern mac. I think iStat can be as much of an evil as a help. People get all obsessed with battery % and temps.
 

CamFire

Distinguished Member
You're missing the point - the high temperatures could be an indication of the CPU(s) constantly running and therefore accelerating the time to the next charge, not a very desirable situation to be in.
 

NewBeetle

Distinguished Member
Could be a rogue browser add-on that doesn't play too well with lion. On the very rare occasion I hear the fans on my MBA running lion, the usual suspect is Firefox plugin process (flash), if I click end task the temps drop off and fans stop, even after the task restarts.
 

darkmast3r

Active Member
I've done some google-ing and it seems I'm not the only one with this problem. Some people say it's indexing but lion continues to remain hot after indexing is finished. In activity monitor there is nothing abnormal going on. I installed no software, only osx lion & istat menu's to test. My cpu is idle but the temp is still higher than snow leopard. I think it's a problem within lion, hopefully apple will fix this problem with an update.
 

Berties

Banned
Like any computer you could try cleaning the CPU heatsink fins and even better cleaning and re-applying fresh thermal paste.
 

darkmast3r

Active Member
No drives are attached only the macbooks internal is used. Berties I dont think its a thermal paste problem or a hardware problem as many other people have reported this after I searched a bit more. Also the temps would be high in snow leopard as well as lion.
 
Last edited:

CamFire

Distinguished Member
Like any computer you could try cleaning the CPU heatsink fins and even better cleaning and re-applying fresh thermal paste.

That's a hell of a job for a laptop!

OP: I still think ActivityMonitor should give you a better guess as to what the offending process is. Otherwise, it could be that iStatPro is not working accurately under Lion, so check that it is updated for Lion.
 

darkmast3r

Active Member
I may try re-seating the heatsink and applying some arctic silver, but I just dont get why lion runs 15º hotter than snow leopard.
 

bpsmith

Well-known Member
CamFire's suggestion might well hold some answers. I can't see how a fresh install of Lion would give such a difference in temps.
 

bpsmith

Well-known Member
Also, do you have Flash installed? A simple Google search on this problem has loads on various forums and Flash is mentioned amongst other things.
 

darkmast3r

Active Member
I don't have flash installed and I've just checked and the logic board has to be removed to re-apply thermal paste, so not really that easy of a job.
 

Spudhead

Active Member
Maybe its your actual Macbook? Im currently browsing the web, playing some music with random youtube video's in-between and my cpu temp in istat pro is only 46c.
 

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