So, I was playing Minecraft with shaders on. I know shaders are heavy on Minecraft but on random times I would get the 60 fps I need but other times it would be 30 fps or 20 fps. When I play my cpu usage is at 20-30% and gpu usage is at 50-75% mostly at 75%. That is when I saw that I was getting 20 fps but the usages were low, I allocate 8GB of my RAM to Minecraft for render distances, the render distances were at 16 Chunks. I uploaded a picture showing my usages over a minute on task manager. IDK why the Minecraft live game isn't showing on the screenshot but I screenshotted it and the game was running at 30 fps MAX and times it would be at like 60FPS if I looked straight up into the sky.
Also, it does show that Minecraft is running at a cap no drops of 60 fps when shaders are off. Utilization 20%.
Intel i7-2700K @ 4.5GHz
16GB RAM @ 1867MHz
AMD R9 390 @ 1500MHz Memory Clock and @ 1GHz Core Clock
(I can overclock the GPU to (~2GHz)1950MHz Memory Clock and 1100 MHz Core Clock(1.1GHz))
PSU 735W 80PLUS BRONZE RaidMax
https://www.amazon.com/RAIDMAX-RX-735AP-R-Authentication-Compatible-Thunder/dp/B076QHHB6X that PSU but the fan Color is BLUE.
I notice you have V-sync running. You'll probably see an immediate improvement by going into "Video Settings..." and change your max framerate to match your monitor's max. In non-Optifine Minecraft, simply turning off V-Sync will fix that. I saw my FPS go from a nearly constant 30fps to something like 45-50fps just like that.
The next thing would most likely be a CPU bottleneck. I run some pretty wicked volumetric lighting shaders on my PC with a RTX 2060S and Ryzen 5 3600X, and I usually run into CPU thermal throttling before I run into GPU issues - I have a stock cooler with an improved one on the way. Minecraft is supposedly pretty CPU intensive, and it is possible that the shaders are also tripping up on the CPU end.
Without knowing what your motherboard supports, I'd guess that your GPU is fine. Looking at PassMark Intel vs AMD CPU Benchmarks - High End and PassMark Software - Video Card (GPU) Benchmarks - High End Video Cards , your CPU / GPU score ratio (a totally unscientific metric I suppose) leans more towards the GPU side than my setup does.
I'm by no means a PC expert, but I hope that helps.
I have an r9 390X myself and a similar problem, its max power state from clocks but only 20% gpu usage so like 40 fps.. the software cant tell the launcher from the game and even after adding manually and setting both to high performance in windows its still no good. Might have to switch back to nvidia if this gets ignored.
Minecraft does nearly everything on one thread. With eight logical processors, 100% usage on a single thread would show as 12.5% in Windows. So your total usage of about 21% easily allows for Minecraft to be completely CPU bound. That, in turn, leaves the GPU with less work to do.