Maybe you can eloborate? What's poor exactly? Relative to other people with a 2400G or to a Vega VII?
What's the full system spec? What driver version?
Some more detail would help. 
Sorry for the late response, I've been recovering from eye surgery the last 2 weeks. 
If it's getting worse, I wonder is the CPU overheating? Could be a paste issue or crooked mounting or something, even the fan setting is too low etc.
Have you checked the load temps with e.g. Ryzen Master or HWInfo?
Have you also run RAM diagnostics? There is a tool built into Windows and also e.g. TechPowerUp's MemTest64.
What speed is the RAM actuallyt running at? Is it using Auto or e.g. an XMP profile?
Any errors (SMART) from the HDD? Maybe run a full surface scan. Are the RAM sticks definitely in the right slots to give you dual channel operation? Running an IGP in single channel will result in terrible performance for sure.
Latest Motherboard BIOS/UEFI installed?
When you say low FPS, I presume this is comparing the same settings and your results to e.g. Youtube videos of others also running a 2400G?
Good luck!
