High temperature when running second display

[cuivenion]

Hi, I'm running a mid/late 2007 Macbook Pro with Mavericks:

http://everymac.com/systems/apple/macbook_pro/specs/macbook-pro-core-2-duo-2.4-15-santa-rosa-specs.html

When I connect a second display the cpu temp goes through the roof, 90C with the fans at max. When I disconnect the screen the temperature comes down. Temperature Monitor shows that it's the CPU's not the GPU that are getting hot. I've looked in Activity Monitor and there's nothing taking up a large amount of CPU that would seem to be causing this.
I've cleaned out the Mac in the last 5 months so I doubt it's a dust build up problem. Any help would be greatly appreciated.

 

[cuivenion]

Hi, I'm baffled by this and could really use a hand. cheers

 

[DeltaMac]

Did you have the same issue before the upgrade to Mavericks?

Your MBPro is at the bottom edge of Mavericks hardware - perhaps the graphics driver is not well optimized.
How much RAM do you have installed? Max is 6GB on that model...
How large is your external screen? Is it using the dual-DVI output (27 - 30-inch?)
Are you using the external display with the MBPro lid closed or open?
If you are really concerned about the heating issues, then you should consider the next step beyond just blowing the dust out. It's 6 years old, and maybe the thermal compound can be replaced on all heat sync areas. It's a challenging job, but should help.
Without doing that, you may also get some relief from fan noise by using one of the accessory laptop cool pads underneath your MBPro

 

[cuivenion]

Hi, I have 4gig of RAM installed. I'm coming out of the DVI and using the apple converter to vga and plugging into the external monitor via vga. The Monitor is only about 20 inch and I've never had this problem before installing Mavericks.
Maybe I should go back to Snow Leopard.
I don't think there's a problem with dust/thermal paste, as it's fine the rest of the time. If it is something to do with the graphics driver do you have any suggestions on what I can do?

 

[dusk007]

I think there is just more graphics acceleration in Mavericks that heats the GPU and to keep it responsive the hardware cannot stay in its low power states. I don't think you can really do anything outside of buying new hardware or going back to snow leopard.

 

[cuivenion]

The thing that baffles me is that it's the CPU that's running at 90c not the graphics chip. If it was the other way round I'd understand it.

 

[cuivenion]

Had a look on Nvidia's site for Maverick drivers, but they only show drivers for Snow Leopard. Looks like I'll have to downgrade somehow.

 

[dusk007]

Under Snow Leopard the GPU doesn't have much to do and stays cool. Mavericks it is probably the CPU has slightly more load and because the GPU is hot too that pushes the CPU heat so high.

I think you just need to go back to SL. Mavericks needs a hardware upgrade. I you should have at least a 2010 MBP for Lion+. 2009 and older are probably better of with SL.

 

[cuivenion]

You're probably right, it just seems strange that it only does it when a second display is connected.

 

[dusk007]

On older GPUs it used to be the case that power saving features were disabled when an external screen was on.
A 750M clocks down to 135Mhz when idle.
My 330M on the 2010 could clock down to the same level with one screen but with two displays the lowest it would go was around 400 Mhz.
An older GPU still might not clock down at all.

If it would be just CPU load, you'd have seen it in the activity monitor.