Nvidia MCP79MX Chip (9400M) Technical Specifications-(Operating Temperatures)

Dear Developers/Friends

I have a laptop that uses the Nvidia Chip MCP79MX (9400M). The chip works as Northbridge as well. I would like to know what are the operating temperatures of the Northbridge Part of the chip (Die 0,1)?

I am having 67-70 Celsius on Idle. Is that normal? What is the maximum operating temperature?

Sincerely Yours

You would need to contact your laptop manufacturer.

NVIDIA doesn’t provide those chip specifications for end-user use.

Furthermore, what is normal is a function of the specific design.

Dear Robert Crovella

Thanx for replying to me so fast. I have already contacted “Nvidia Online Chat” and the “Apple Online Chat” about the specifications and they don’t know. It seems you don’t know as well.

Have a nice Day

I have no knowledge of the chip specifications, but observe that both my NVIDIA GPU and my Intel CPU routinely reach slightly over 80 degrees Celsius under load, which is close to 24/7 in my case.

At idle the temperatures I observe are closer to 40 degrees Celsius for either chip, but this is in a well ventilated workstation enclosure, not the tight internals of a laptop. Depending on how the cooling works in your laptop and how old the machine is (based on the chip type, I am guessing around 10 years?), it seems a distinct possibility that airflow for cooling may be impeded by dust accumulation. Last time I looked at the inside of my machine, heat sinks and fans were covered by a thick layer of dust.

Dear njuffa

Thanx for replying to my thread. The problem is with the Northbridge temperature , not the GPU. You didn’t understand my question. The MCP79MX is multi function chip, not only GPU and has 3 temperature sensors on it.

Have a nice day

I think I understood your question alright. As I recall the MCP79MX was a Northbridge with integrated GPU, made by NVIDIA ca. 2010 (this may have been the last part in the MCP line before NVIDIA stopped making such parts).

Semiconductors that go into the same product tend to have similar thermal characteristics. By looking at CPUs and GPUs we can reasonably speculate (in the absence of a data sheet) how hot chips in their immediate vicinity may be allowed to run. Anecdotally, for modern chips the answer seems to be 80-85 degrees Celsius. I seem to recall that the thermal bounds were a bit higher with semiconductors built in older manufacturing processes, where the limits were more around 90-95 degrees Celsius.

Your reported temperatures (at idle, I note) are lower. You haven’t shared what they are under full load. I don’t know what the concern is which prompted your original post. That the MCP79MX could soon fry itself? Given that the part is possibly nine years old at this point, it is best to assume that, depending on duty cycle, it may be on its last legs anyhow.

Hello Again

The problem is that “Apple Hardware Test” finds the temperature of "Northbridge Die 1"reported higher than expected. I have cleaned the fans , reapplied thermal paste and everything is fine (GPU and CPU). There are 3 temperatures on the MCP79MX.

The “Northbridge Die 1” Temperature is on MCP79MX and I want to know the specifications of the chip if possible.

Sincerely Yours

What temperature did you expect, and why? If you somehow were able to confirm that the measured temperature is indeed higher than it should be, what action(s) would you take?

As I said, I don’t have the datasheet. I searched for a datasheet on the internet but couldn’t find one. Datasheets for this chip were likely furnished only to companies who built products with it. For all I know the datasheet may have been covered by an NDA, in which case few copies could be expected to float around.

Dear njuffa

Thanx for your help. I would stop writing to this thread. I hope it doesn’t insult you. I can’t find the data sheet either.

Have a nice day

A statement by NVIDIA from around the time the MCP79 was produced:

NVIDIA GPUs are designed to operate reliably up to their maximum specified operating temperature. This maximum temperature varies by GPU, but is generally in the 105C range […]

A quick internet search shows a fair number of complaints about the MCP79 running hot, e.g.

My 9400 hits 90-94c when gaming. Idle is normally about 75-82c That was with it enabled and with it disabled (You can check 9400/MCP temp in Everest when it is disabled)