So this Weekend I got to put the new lappy to the big test with a Ghost Recon Wildlands session Friday night.
Things where going awesome for the 1st 15 min.  Then it started having frame rate drops to 3 to 4 FPS for up to 5 to 20 second periods of time. 
 
I run a cooling pad and boost fan so CPU and GPU temps stay just over 70 to 75 degrees so that was not an issue.  I tried lowering the details.  I reset the Nvidia Experience and re-optimized and that helped not at all.  Sp now I am very worried.  Seems when I was playing for short sessions 5 to 10 minutes it was great.  But as soon as it goes over 15 minutes it starts having fits and they get progressively worse.  And you do not have to be doing anything in game, you can be sitting at a stand still and suddenly 2 FPS for up to a full minute. 
 
Really need a clue here.  Love this laptop but I can't have this.  Checked the HD activity and it is not that it is having a hard time pulling textures.  I am really just at a loss.  Like I said you can just have your toon standing still doing nothing and it will go into this mode  and you never know if it will last for just a couple seconds or longer.
 
This is pulling the joy out of this totally awesome laptop for me.  I hope some one has some help for me.  ^_^

The 7700hq cpu is gonna be eaten up by that game. I know because I use this laptop for that game. Use ddu and reinstall your drivers and don’t install that GeForce experience junkware either when you use ddu to wipe clean. I turned off turbo boost for my cpu to get lower temps as after gaming for a few hours my cpu would go high 80’s. With turbo boost off I see low 70’s after hours of gaming, and the 1060 6gb isn’t enough to bottleneck the cpu at 2.8ghz with turbo boost off. Make sure you have adaptive selected in nvidia control panel for your gpu power and high performance is selected in windows power settings.

Athena
I checked that when I got the lappy, it did not have any of the extra Nvidia stuff installed.  Not that that would cause such drastic frame rate drops, but I do like to run my kit clean.
 
You do know what the Geforce Experience does right?  All it does is suggest optimized game settings based on your kit vs the games needs and then you adjust from there.  No over head if you are thinking there might be.  Unless you have some inside scoop I do not know about.  Please let me know.  :)

A quick google search can show you how broken geforce experience is and even the nvidia moderators on the nvidia forum recommend uninstalling geforce experience to remove headaches.  There is a reason its optional and not forced.  Make sure your on the latest nvidia driver and have it cleanly installed then go from there. Corrupt driver can cause bad FPS, and lockups. DDU and clean install.

Thanks good info.  Wow  O_o
 
I will clean that off tonight and give it another go.
 
I must have been getting lucky my laptop CPU never got over the mid 70s yet.
 
(thanks for the info guys I had been using the Experience on my desktops since they did that you want new drives you have to have this.  And it did improve my GTA performance greatly on both desktops with just one click.  But its not worth all this.  Cleaning it off all my PCs now after reading that stuff. 

If you haven't already, I'd also check to make sure you are using the most up-to-date version of the BIOS for the SC15. The Windows 10 Spring updates have had some odd issues and updating to the latest 1.06 BIOS tends to resolve it. You can find instructions on how to update the laptop's BIOS at the link here: http://www.evga.com/support/faq/?f=59717.

Sounds like a power delivery issue if you're not overheating. What do your cpu & gpu clocks look like before & after the drops occur?