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ncrypt

macrumors 6502
Original poster
May 16, 2012
351
257
UK
I have a new mid-2014 15" rMBP with Iris Pro graphics. The system idles at around 40-50ºC, but if a screensaver is on (any of the standard OS X ones), the CPU temperates increases to anywhere between 80-9ºC.

Any thoughts on why, and whether this normal?
 
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cjmillsnun

macrumors 68020
Aug 28, 2009
2,399
48
No idea, however screensavers are unnecessary now that CRT screens are something from the past.

I just have my screen switch off after a minutes inactivity instead and the power consumption and heat goes down.
 

dusk007

macrumors 68040
Dec 5, 2009
3,411
104
Screensaver taxes the GPU and the CPU which will heat it and the cooling system doesn't really aim for anything much lower than 90C.
Just don't use screensavers. They aren't good for notebooks. They just heat unecessarily. They shouldn't really be called screensavers anymore as they don't do anything useful, they are more harmful than good and only look pretty. You save the screen by just turning it off.
 

redheeler

macrumors G3
Oct 17, 2014
8,419
8,841
Colorado, USA
Wow, I can't imagine a screensaver stressing the GPU that much when even a 700 MHz eMac can handle one without dropping a frame.

If you're concerned, just turn screensavers off.
 

SarcasticJoe

macrumors 6502a
Nov 5, 2013
607
221
Finland
That really doesn't sound right... A screensaver shouldn't stress the machine anywhere near as much as to lead to those kinds of temperatures. When I let my machine sit on it's own til the screensaver goes on (which usually only happens when I'm having the machine play music when I'm reading a book, doing university course assignments on paper or cleaning) it doesn't get any hotter than it's typical idle temperatures of around 40-50c.

When I think about it, the only logical thing I can think of is some kind of background processing (like Finder indexing, Folding@Home, etc.) combined with ether clogged up or otherwise malfunctioning fans.
 

cjmillsnun

macrumors 68020
Aug 28, 2009
2,399
48
Screensaver taxes the GPU and the CPU which will heat it and the cooling system doesn't really aim for anything much lower than 90C.
Just don't use screensavers. They aren't good for notebooks. They just heat unecessarily. They shouldn't really be called screensavers anymore as they don't do anything useful, they are more harmful than good and only look pretty. You save the screen by just turning it off.

The screensaver should tax absolutely nothing. It's a simple process that has been around since before OS X.
 

Freyqq

macrumors 601
Dec 13, 2004
4,038
181
This has been an issue since forever. Just set it to turn the screen off after a certain time instead of using a screensaver.
 

ncrypt

macrumors 6502
Original poster
May 16, 2012
351
257
UK
Quite surprising that so many of you find this normal. I used to have a 13" rMBP and the temperature never rose when the screensaver was active.

Thanks for your suggestions to turn off the screensaver, but that isn't the solution here. That kind of temperature seems abnormally high that I've never seen on my previous Macs, is it worth taking it to Apple and seeing what they say about the temperature increase?

Also, CPU usage stays low at 1-2% percent whilst the screensaver is active so pretty sure there are no background tasks running.
 

MagicBoy

macrumors 68040
May 28, 2006
3,947
1,025
Manchester, UK
When I think about it, the only logical thing I can think of is some kind of background processing (like Finder indexing, Folding@Home, etc.) combined with ether clogged up or otherwise malfunctioning fans.

Can't see it being clogged up fans on a new 2014, unless OP works in a cotton processing plant or uses a pet cat as a makeshift desk. ;)

My money's on Spotlight if it's box-fresh.
 

maflynn

macrumors Haswell
May 3, 2009
73,481
43,405
The easiest solution is to put the display to sleep. I have no ida why a screen saver will chew up so much cpu cycles that would generate that much heat.
 

SarcasticJoe

macrumors 6502a
Nov 5, 2013
607
221
Finland
Can't see it being clogged up fans on a new 2014, unless OP works in a cotton processing plant or uses a pet cat as a makeshift desk. ;)
Trust me, if there's a way to get the fans of a 2014 model computer to clog by January 2015, then somebody will find that way, be it by accident or on purpose.

There's plenty of pictures floating around on the internet from tech support horror stories with computers that have fans clogged up by cockroach infestations, spiderwebs, saw or concrete or dust, dead rodents or just tar from people smoking next to their computers.
 

MagicBoy

macrumors 68040
May 28, 2006
3,947
1,025
Manchester, UK

OPs had the machine a couple of weeks. ;)

I'm fully aware of dust, infestations etc - I've been working in IT support for 15+ years. My favourite was a ThinkPad infested with mites that belonged to an Environmental Health Officer. At first glance it looked a bit dusty, Then I noticed the dust was moving. It got bagged up as hazardous and fumigated by the pest control guys! Eww!
 
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ncrypt

macrumors 6502
Original poster
May 16, 2012
351
257
UK
Good news! The issue has stopped occurring and now my system temperature does not increase when the screensaver starts.

MagicBoy and SarcasticJoe were probably right with it being spotlight or something since the machine is <5 days old and I have been transferring data to it.
 
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