I bought a LG 4K monitor that has AMD FreeSync because there was a huge discount for Prime Day. Arrived today haven't unpacked but my PC actually has a GeForce 1080...

Did screw up and but the wrong monitor? Or does FreeSync/GSync not matter much?

Freesync is a free standard (unlike nvidia's gsync certification, that does the same thing but for nvidia gpus only and for a large markup).

That said, only a few freesync monitors can actually use that feature with an nvidia gpu, so it's most likely as if you didn't have it at all (depends on the model though).
Which is kind of a bummer, since it's a very good feature for 4k gaming: it adapts the screen's refresh rate to the fps of the gpu, so when you drop below 60 fps you still get a smoother feel for movement (instead of choppiness).

Sooo yeah, if you wanted a gaming monitor you probably should have gone for 1440p 120/144Hz with gsync

With driver update from a few months ago NVIDIA unlocked a limited FreeSync capability for its cards.
But I don't know if your monitor is supported.

Even if it isn't, you can 'force' FreeSync, but of course it isn't guaranteed to work.

Check in the Nvidia Control Panel (not GeForce Experience), you can force enable "Gsync Compatible" with any FreeSync monitor, but your milage may vary.

Personally MY 27"/1440p/144Hz ViewSonic XG isn't Gsync certified but works a charm.

@kwilliams I haven't switched monitors yet but actually I turned on 60fps with my current monitor which is HP FHD I think.

Playing Forza Horizon 4 which is basically the only game I play and apparently there's an option to show FPS stats. It's rendering at 50% GPU.

Resolution though is 1920x1080. So send very smooth now.

I guess with 4K the resolution goes up so GPU usage would increase to like 100%?

@billgates 4K is 4× HD however resolution scale is an exponent to the computational power required for rendering. If you are at 50% for 1080p/60 you're realistically looking at 1440p/100 at the top end.

What are the rest of your specs?

@kwilliams not sure what you mean by exponent. But this is the machine I have https://newegg.com/abs-computer-tec...

@billgates a respectable system, especially in that price range.

1440/144 is what you should aim for.

@kwilliams thanks though to late now... Went ahead and bought the 4K for $300 since it was a Prime Day deal.

Guess will see what works... Biggest issue I think is the strain on the GFX card at 60fps. Usually it's around 40C for 30fps but even with 1080 went upto 60C after about an hour of play.

@irene Oh it is? Hm... I just saw was 20C hotter than usual. So at what temp does it become concerning? 80?

@irene 4K seems to use 96% GPU, temp peaks around 75-80 though...

But actually it seems the biggest difference is from switching from HDMI to Display Port.

Had both plugged in at first as I thought needed both... When I turned it on, I was like WTF, picture quality is pretty much the same....

I noticed though there were 2 monitors and then Googled HDMI vs DP... and realized your not supposed to use both.

But it kind of feels like the biggest contributor is just the cable? DP has more bandwidth.