When Minecraft starts, the full CPU power of Java (TM) Platform SE binary is used and the game is super slow. What can I do?

I have a 5 year old Lenovo laptop with an i5 processor and 8 Gb of memory. Minecraft always ran very smoothly on it. Now I bought a flash memory, installed it and then reinstalled Windows. The laptop now runs very quickly again compared to before. However, Minecraft is now running very slowly. I downloaded Minecraft as normal, played in vanilla and without a resource pack or the like. As a test, I reduced the visibility to the minimum and then even started Minecraft with 4 instead of 2 Gb of RAM.

However, the game is very slow. My frequency is around 1 frame / second. The task manager shows that the CPU performance will increase to 96% - 100% from the start of the game. Here, Java (TM) Platform SE binary pulls all the power. I've tried uninstalling and reinstalling Java, but it doesn't change anything. Even while the app is uninstalling, it will open when Minecraft starts and draws all of the CPU. I installed all Windows updates and downloaded and installed all of the Lenovo graphics card drivers.

What can I do to be able to play Minecraft properly again with the laptop?

Hi, is the CPU utilization only that high when you have MC running, or always?

The CPU utilization is usually 3% in the normal state. As soon as you press PLAY in the Minecraft Launcher and Minecraft opens, the CPU then increases directly to 100%.

Okay, strangely enough, a friend of mine has that too, despite the better hardware, my idea would be to put the laptop back on again… Or which java version do you have?

All right, I could still try that. The Java version is 8.0.51.16

Okay, java is the newest… But someone else may know…

Thank you anyway