Minecraft FPS Low, When Build is Amazing

[aneesh.x.kumar]

When I run minecraft on high settings I typically get around 100-200 fps, at 4k resolution. The thing is, when I make it fullscreen, there are lots of gray bars that go through my screen every time the fps fluctuates, and after I turn on vsync, the entire bottom half of my screen goes black, so I run minecraft in windowed, and expand minecraft to fit the screen. (Then it works okay)

My main problem, when I run a shaderpack, my fps drops to 30, about only 10% of my cpu is being used, and about 80% of my gpu. My friend with a 960 and an i7-8700 gets 150fps with the same exact settings.
The shaderpack I'm using is Continuim shaderpack, and I feel like my pc should be able to get at least 60 fps.

Specs:
GPU: RTX 2070
CPU: i9-9900k
RAM: 16gb DDR4-2400hz

 

[cookiemania66]

I would suspect that your GPU is faulty due to all the artifacts and problems you mentioned.
You should have warranty on that card and i would use it. Doenst sound good.

 

[SkyNetRising]

My friend with a 960 and an i7-8700 gets 150fps with the same exact settings.

Your friend doesn't use 4k.
Try monitoring vram usage with MSI afterburner. You might be hitting available vram limit with 4k there.