Started with upgrading from a 1080ti to a 3070. My CPU was old so just upgraded the MB and the CPU (i5 10600k). Now its time to upgrade the monitor, which is 1080p 60hz. I wanted to go 1440p at 80 to 144hz. I cannot seem to find a G-Sync. Amazon search returns tons of Free Sync and Adaptive Sync. As I a bit behind on these technologies, will either the Free or Adaptive work with Nvidia? 

A quick hint for you... I just purchased a Samsung G7 Faker 32" 1440p monitor... stay away, it's garbage.
 
However, my last two monitors from ASUS have been AMAZING. I have an old ROG Swift 27" monitor that's G-Synch 165hz, and 1ms response; its a few years old and still outperforms newer monitors on the market. ASUS just came out with the ROG Swift 32" 175hz, 1ms Fast IPS (PG329Q) monitor, it's a BEAST and the best monitor I've had thus far.
 
 

aka_STEVE_b
For me personally, Samsung was the worst experience  for quality & service ,..ever !!
 
Asus, AOC , LG , maybe Acer & Pixio are worth a look
..and again, in my opinion , dont worry about Gsync . It's like a $200 premium over any other monitors...

^^^This post...my experiences with Samsung for 'monitors' have been horrid. I'm slowly becoming an ASUS fanboy. Also agree on the GSync... I think I've used it a couple of times in games, and it really doesn't make that much of a difference.

Nvidia publishes a list of all G-Sync monitors on their website:
nvidia.com/en-us/geforce/products/g-sync-monitors/specs/
 
Just a heads-up, there are multiple tiers/levels of G-Sync:
tomshardware.com/reviews/nvidia-gsync-monitor-glossary-definition-explained,6008.html
 
"G-Sync" and "G-Sync Ultimate" both require a built-in, dedicated Nvidia controller which often increases the overall monitor price. However, the "Variable Refresh Rate (VRR) Range" typically spans the panel's entire refresh range.
 
"G-Sync Compatibility" doesn't require the proprietary controller. The "VRR Range" usually starts around 40Hz-48Hz and extends to the monitor's maximum refresh rate. If the monitor lists "FreeSync" or "Adaptive-Sync" it is also typically "G-Sync Compatible".

Turn off adaptive. Set hard limits for FPS/refresh rate around 120-140 on both the monitor & NVidia control panels.

It was just incompatibility with the MAG272CQR and G-Sync. I switched to the Acer Predator XB271HU 27", which is G-Sync and it works great.

Wow, I've been looking at the MAG272CQR, too, glad I stumbled upon this thread! I am probably going to go for the Dell S2721DGF but that Acer Predator was the first one I had my eye on. I have a 1080p 60hz Acer now that is still working fine, but like you, I got an RTX3070 and decided it's time for something else.