MP 1,1-5,1 Mac Pro 2009 - Spike in North Bridge Temperature

[socamx]

About my Mac Pro: It's a 2009 model with the 4,1 -> 5,1 firmware upgrade, dual CPU with 3.33ghz upgrade, 24gb of ram (8x3), Radeon RX 580 with boot screen (prior to yesterday RX 480), USB 3.0 PCIe card, SATA PCIe adapter for its boot SSD. 2x 4TB, 2x 2TB HDDs in the four bays. It's running Catalina.

Today on the 9th I noticed North Bridge TDiode and North Bridge Heatsink spiked up in temperature by over 10 degrees since July 4th. I installed the GPU yesterday, the 8th so I don't think there's any connection with that.

Is this something I should be alarmed by, a sudden 10 degree spike in temperature? What's a temperature where you start getting alarmed?

The attached screenshot is the 30 day history for the TDiode temperature.

 

[KeesMacPro]

If you were not e.g. benchmarking the new GPU, i'd check the NB rivets .
I'm not too familiar with Fahrenheit ,but the delta NB diode -NB heatsink should be ~ 5-12 degrees Celsius.

 

[socamx]

Northbridge heatsink is at 149F (65C), diode is at 172F (78C) currently. Prior to July 5th they were much closer in temperature. So I'm guessing my heatsink is coming loose?

Edit: I took a peek inside the case and the one exposed rivet you can see on the Northbridge heatsink appears to still be in place correctly. Guess I'll have to take the CPU tray out to even see the other one.
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Okay it gets a little weirder. Exhaust, Booster 1 & 2 and Intake fans all have been running lower speeds around the same time too.

If I recall correctly, I finally restarted the Mac Pro around this time after it having been up for at least 47 days straight. Perhaps for some reason after rebooting my fans are just running at a lower RPM, making the Northbridge temperatures go up a bit?

 

[KeesMacPro]

Northbridge heatsink is at 149F (65C), diode is at 172F (78C) currently. Prior to July 5th they were much closer in temperature. So I'm guessing my heatsink is coming loose?

Delta of 13 degrees is fine, as long as its not getting >~15/20 degrees, the heatsink is still attached. Delta can vary depending e.g. on the load.

my fans are just running at a lower RPM, making the Northbridge temperatures go up a bit?

Definitely yes.
I don't know your fan setup, but i'd recommend to check the setup, see if something's changed.
Assuming the fans are not set at default...

 

[socamx]

According to iStat Menus the fans are all system controlled. As far as I'm aware I've never done any tinkering or overriding of fans settings.

It sounds like as of right now there's nothing to worry about, just for some reason a system reboot made my fans run at a lower speed and thus brought up the Northbridge temperature. Maybe a process was running away from me and I didn't notice it making the CPUs work harder.

My CPUs usually sit at 136F (58C) and 104F (40C)if that makes any difference.

 

[KeesMacPro]

Looks all okay to me too

Personally I prefer to set Intake and Boost A depending on the NB diode Temp, so it stays around 60 degrees Celsius.