So, no one is using this notebook here ?

I Know @robert p has delt with this problem before.

Both my brother and I had brand new G7 7790's and both have this issue. What was the outcome of idiscodancer's case Robert P?

Did you solve the issue ?

I managed to solve it using external utilities like Intel XTU or Throttlestop (both are doing the same things with a different user interface). 

The issue seems to be related to the CPU failing to properly idle under light or no workload at all, with a lot of "spikes" at maximum frequency of 4 Ghz.

I applied a little of undervolting and I set a less aggressive rump up of the CPU (playing with Intel Speed Shift EPP parameters), so now my CPU stays around 36/40° C when browsing and goes up to 78/85° C when playing, which is fine.

I also have this CPU in a G3 3590 and run 90-100 playing any game. However, disabling Turbo Boost and undervolting CPU Core and Cache reduced my gaming temps to around 85 max. Idle temps between 45 and 50 with no fan noise And I haven’t seen a drop in performance as the 1660 ti is doing most of the work. You can use the BIOS settings (F2) to disable TurboBoost

I beg your pardon, but I consider your as a very poor solution. You are basically taking a 4.5 Ghz CPU (4 Ghz all cores) and limiting it at 2.6 Ghz disabling Turbo Boost. You are almost halving the performance.

I would suggest you to use Throttlestop or Intel XTU for a light undervolt ( -100 mV is enough and it is well tollerated by i7 9750H), and you can limit Turbo Boost at 3.8/3.9 Ghz for all 6 cores, in order to avoid spikes of temperature above 90° C.

With the above settings, and playing with Speed Shift - EPP, I'm playing with temperature at around 80/85° max, but with CPU clock in the 3/3.5 ghz range, much better than 2.6

I cannot seem to get Throttlestop to work on my g7 7790.  Is there a trick I'm missing here?  All of the undervolting settings are greyed out and wont let me click.  Only disabling turbo boost.  But I can do that theough the bios.  As you have said I would like to avoid doing so also..

You probably updated your bios to the last version and even windows to the 2004 update.

this could prevent ThrottleStop to work.

try to enter the bios and reset values at default. In some cases it works and undervolting will became available again.