Is it possible to turn down the frequency on a LG 5K Ultrafine and will it help reduce GPU heat?

My MBP15" often overheats (forcing fans to full) when plugged into my LG 5K Ultrafine. I understand that it runs at 60Hz and that this puts strain on the GPU. Since I'm mostly coding/browsing I wanted to test out 30Hz to see if it reduces the heat levels, but I don't see any way to control this in the UI. Is this some hidden advanced menu or CLI method?

Clarification: My machine is not shutting down, so Apple's fan speed logic seems to work fine in my case. I'm looking for ways to reduce the heat output so that high fans speeds are hopefully not required at all.

Solution 1:

It's not possible to change the frequency and the physical resolution of this display.

IMHO changing that will not lower the thermal load of your MBP, because once you connect an external display the "external" GPU will be used and it has at least 10W of consumption. This is very apparent in the newer 16" MBP, where I measured ~20W of base load with no matter how many or what kind of monitors are connected.

edit: You can change the resolution (by option-clicking the Scaled label) or control-clicking Display preferences to show additional resolutions), but (at least on my setup) it barely makes any difference.

Solution 2:

According to the monitor manual, the monitor itself does not support 30 Hz.

In the section regarding "Signal Timing" they only list 60 Hz as supported. In the product specification sheet, they write that the vertical frequency can be 48 Hz to 60 Hz.

Therefore I do not think 30 Hz is achievable with this monitor.

Solution 3:

As addition to the other answers - changing monitor refresh frequency will do nothing in this case (I.e for some TB3 external monitors that would allow that)

Monitor frequency defined on monitor and as driven by monitor hardware. The heating of your MacBook comes from discrete video card that is used to communicate with external monitors. And it heats up due to new MacBook Pro poor heat dissipation design. Which has nothing to do with monitor refresh frequency.