Hi RaphaelBeldzik,
Thank you for reaching Microsoft Community. I'm sorry to hear about the issue that you are having with the RAM of your Surface Pro 7. We'll work together to find out the what's causing this issue.
May I know what do you use in doing the test to get these details? Is it through the Task Manager or using a third party app?
Does the issue happens when the device is plugged in or also when running on battery?
What are the peripherals or accessories connected to the device?
Please check first in Task Manager, under the Startup tab. Check what are those applications that runs on startup and disable applications that you do not need immediately when the device boots up.
Run these steps below also then check if the issue persist:
1: Run Surface Diagnostic Toolkit
See: Fix common Surface problems using the Surface Diagnostic Toolkit (microsoft.com)
2: Check for Windows Update
Go to Windows Settings > Update & Security and select Check for updates
Make sure all updates need are installed including Optional updates
3: Update drivers and firmware
Check what is the current OS Build of your Windows version by going to Settings > System > About.
Go to Download driver and firmware for Surface, choose Surface Pro
Then click the link next to Surface Pro 7 then click Download on the next page.
Choose the .msi file that matches your current OS Build and click Next.
After downloading, run and install the .msi then Restart.
4: Run System File Checker Tool
See: Using System File Checker in Windows (microsoft.com)
Hope this helps.