macbook - incessant CPU spikes while fan running

[whitecat]

The subject line says it all really. Didn't notice it before 7.3 (which doesn't mean it wasn't an issue, maybe the fan just never came on while I was working before), but whenever the fan comes on in my Macbook the CPU meter starts going all over the place, spiking/overloading repeatedly and quickly. I can't use Pro Tools at all until the fan completely shuts down, and I need to click somewhere on the application (even though it's at the front). It'll just click & pop if it makes any noise at all while this bizarre behaviour is occurring.

Running LE 7.3.1 on a Macbook Core Duo 2.0GHz, 2GB RAM, 10.4.8, using an external FW drive for audio and using an Mbox 2 Pro.

Any ideas?

[tele_player]

You might be getting this backwards. Whenever the CPU gets busy, it generates more heat, and causes the fan to speed up.

So, the issue isn't how to get the fan to run slowly, it's how to eliminate the CPU spikes.

[whitecat]

yeah, it's probably related but the problem seems stranger than just that being the obvious answer - I'll elaborate...

I was running a session today which was just pianoteq and the waves ssl channel. with the buffer very low (128), the digi cpu meter was reading around half. I had the session open, when I took a break to check my email on my 'office PC,' so nothing was really happening as far as input (just the CPU overhead from having the plug-ins 'on' but no audio going through them). the fan came on and the CPU meter starts to show spikes and it's going all over the place (the single green line was flying left and right). This happened several times during the day. when left to its' own devices, eventually when the fan shuts down everything is back to normal. however, I did discover just now that if I click anywhere on the pro tools application once or twice, the fan continues, but the CPU stabilizes and I can continue working with no audio interruptions. eventually the fan will shut down of its' own accord.

no other applications are running, BT and airport are OFF, etc. etc. so I'm wondering if there's some other funny processes, specifically IN Pro Tools 7.3.1 that are destabilizing this whole thing.

make any more sense?

[DigiTechSupt]

Do you have your energy savers turned off?

What items are in your MacHD>Library>StartupItems folder?

Do you notice any other applications or utilities running that may be interfering with Pro Tools?

[whitecat]

Do you have your energy savers turned off?

What items are in your MacHD>Library>StartupItems folder?

Do you notice any other applications or utilities running that may be interfering with Pro Tools?

Yes, Energy Savers are all disabled completely.

StartupItems: there's a folder for each of Aladdin (I assume that's Stuffit Expander), Digidesign Mbox 2, DigidesignLoader, PACESupport and Qmaster.

There is nothing else running while this occurs - even stranger, is the Activity Monitor isn't really picking anything unusual up, but the PT CPU meter is, as it's moving all over the place.

Again, clicking on the Pro Tools application seems to stabilize the CPU (even if the application is in the foreground/being used). So it's only a catastrophic problem if the fan comes on while I'm laying down a track or in the middle of playback, but it's still annoying.

Thanks!