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MP 1,1-5,1 Temps good and bad

G

GoJohnGo

macrumors newbie
Original poster
Feb 18, 2022
24
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I'm getting ready to refresh/re-paste/Northbridge re-anchor my 4,1 and three 5,1 machines. I've read quite a few threads where people generically reference their "temps" as being "high" without specifying which temp they're measuring and what the reading is, and, while seeing snippets of guidance, haven't found the info all gathered in one place.

So, I'd like to ask, for a 3.46GHz dual processor (let's take probably the hottest setup here):
Which temps are important to monitor (I assume the CPU A, CPU B, and Northbridge Tdiodes)?
Which deltas are important to monitor?
What temperature range for each important sensor and/or delta would be considered normal?
What temperature range for each important sensor and/or delta would be considered high?
What temperature range for each important sensor and/or delta would be considered shutdown time?

I'm assuming the standard Mac fan control program here. I expect the fan speeds are probably part of the equation as well, as the fans could speed up and actually mask a potentially hot component.

For those of you using custom fan profiles or adding additional cooling:
What temperature range for each sensor and/or delta would be considered ideal?
I assume all that work is meant to meet some target, right?

I'm doing benchmarks (temps at idle and after running the Prime95 torture test for an hour) before and after to see if my work improved anything, but it would be quite helpful to know a) if there's anything abnormal about their current condition, and b) what good targets are for the temps after my work is done.
 
Okay, I almost have my first data point. What sensor does "IHS (integrated heat spreader)" map to?
SensorNormalHighShutdown
IHS (Integrated Heat Spreader)78.5
 
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GoJohnGo said:
Okay, I almost have my first data point. What sensor does "IHS (integrated heat spreader)" map to?
SensorNormalHighShutdown
IHS (Integrated Heat Spreader)78.5
Click to expand...
I believe it’s a throttle temperature not a shutdown temperature.

As for the sensors name I’m not sure. Don’t have one of the old Mac pros to check with. CPU package possibly if you have that value
 
GoJohnGo said:
Okay, I almost have my first data point. What sensor does "IHS (integrated heat spreader)" map to?
SensorNormalHighShutdown
IHS (Integrated Heat Spreader)78.5
Click to expand...
That T-case temperature is not measurable in a normal setup. And there is no sensor can tell that temperature on the cMP.

In real world usage, you mainly check the T-diode temperature. According to the Intel Processor Diagnostic Tool (Windows only), the max T-diode temperature for the Westmere Xeon is above 100°C (e.g. 101°C for my W3690, from memory, the max for X5690 is a bit higher, something like 103°C).

The cMP's native fan profile should keep the T-diode below 90°C. Since CPU A is always warmer, when the cMP is under full stress, you can expect CPU A reach 90°C, and CPU B is around 80°C. If the heatsink is a bit dusty, the temperature spike may go above these temporarily, but shouldn't be too close to 100°C.

And even that 103°C isn't the shutdown temperature, but just the max allowed normal operating temperature. Technically, the CPU can stay working at that temperature 24/7.

Once go above that, thermal throttling should kicks in, and keep the CPU temperature right at that max temperature.

But if the cooling system is really failed, and even max thermal throttling still can't suppress the temperature to go up, then the T-diode can go up to above 120°C, until it hit the hard shutdown temperature. Intel never state what that shutdown temperature is, but you can expect that's something like 20°C higher than the max allowed operating temperature.
 
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GoJohnGo said:
Which deltas are important to monitor?
Click to expand...
Apart from all the diode temperatures, you should also monitor the heatsink temperature. The delta between diode and heatsink can tell if the cooling system is working properly.

For long time idle, the delta between CPU diode and CPU heatsink can go as low as 1°C. But in general, after a short period of idle, the delta should be at around 5°C.

However, what really matter is the delta when under stress (e.g. after 5min of running Prime95). The delta should be around 15°C. Of course, the lower the better. But even it is a bit over 15°C, there is nothing to worry about. However, it shouldn't be above 20°C. If the delta is something like 30°C, then the cooling system is failing (e.g. usually due to incorrect thermal paste application).

Northbridge is similar, around 15°C delta is normal. The lower the better.
 
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Okay, here's a shot at the next version of the table:
SensorDesireableNormalLoadedExcessive
CPU A - Tdiode??up to 90˚C103˚C
CPU A - HeatSink?<5˚C from Tdiode<15˚C from Tdiode>20˚C from Tdiode
CPU B - Tdiode??up to 80˚C103˚C
CPU B - HeatSink?<5˚C from Tdiode<15˚C from Tdiode>20˚C from Tdiode
Northbridge - Tdiode???>75˚C
Northbridge - HeatSink?<15˚C from Tdiode<15˚C from Tdiode>20˚C from Tdiode

I think I've represented what's been written so far. I added the Northbridge - Tdiode Excessive cell entry from a conversation with @tsialex where he mentioned the fans kick in at that point.

I also added a "desireable" column for the fan tweakers. I'm curious what your targets are for your efforts.

So, how about the remaining question marks?
 
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