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Hi,

I made a page showing how to reduce the Mac Pro Northbridge chip temp.
My Mac Pro is a Sept '07 Dual Quad core 3Ghz, 9 Gig RAM, ATI X1900XT. I got annoyed that without any mods that Hardware Monitor showed the Northbridge running at 80°C (176°F) (idle). It took a while to work out but I have reduced the temp (at idle) by 35°C with a couple of simple mods. My Northbridge currently sits at 45°C with a bunch of heavy apps running.
If you are completely hopeless with machines of any kind don't try this.

Untitled Document

MIKX

Very impressive. Perhaps you could teach Apple's engineers a thing or two.

Did you confirm those temperature measurements with another probe? Cheap thermal sensors aren't known for their accuracy/calibration and I find it hard to believe Apple would ship them like that when the max operating temp is 83.8C.

Yes but only after I did the mod and it showed slightly lower temps than the sensors. The Northbridge is rated (I think) to over 90°C but what I was worried about with the initial 80+°C temps I was seeing was how the Northbridge was contributing an immense amount of heat to the case environment, I was worried about the long term effect of prolonged high case temperatures, especially in the PCI bay and RAM cage area. The Mac Pro Southbridge has a bigger but still inadequate heatsink and is right next to the upper RAM cage, replacing the existing Southbridge heatsink will be my next project but I will have to put up a "Stage 1 Mac Pro Dis-Assembly" page first as the entire RAM cage needs to be removed to work comfortably on it.

My Mac Pro Quad 2.66GHZ is running at 56ºc without any mods according to iStat Pro.

My first Rev Mac Pro (4x 2.0 GHz) has a very hot northbridge as well. With even minimal apps open and most resources free it still runs around 78-81 C. I always wondered why it was so much hotter than the rest of my components. My cores all have temps of considerably less, and no where else is close to these temps, even my various RAM sensors are way less.

It seems like half of the effectiveness from this mod comes from the fact that the new graphics cooler he put on has a larger fan just below the new heatsink of his northbridge (which he mentions in the link).

I would be curious how much the northbridge (still with apple's original heatsink and thermal paste) would be reduced by the thermaltake cooler. Then again, what actual difference that larger heatsink (and better thermal paste) would make. I'm interested in doing this, but not for very small gains (I currently use the Zalman VF1000 on my X1900XT, which does not have the same fan positioning.

You might get more credibility if you, like, put a title on your web page. Just a thought.

The implication that Apple's hardware team is lacking (in, say, the grinding off of a heatsink) is way out of common sense bounds. The "as is" cooling system will keep all components below their specified rating, so no real "issue" exists.

HI everybody,
another solution ... without any temperature reduction. Is the temperature indicated by Temperature Monitor come from the southbridge (same area as the memory cards)??

It may be below their specified maximum temperature, but that's still very hot. Certainly you want your components running cooler if you have any choice.

Intel says the northbridge is rated to 83.8C.
Changing the temperature doesn't significantly affect heat output.