CPU:AMD FX ™-4300 Quad-Core Processor 3.85GHz,2 Cores,4 Logical processors.
GPU:AMD Radeon R7 200 Series
RAM:8GB
Motherboard: AsusTeK M5A78L-M LX3
Hard Drive: 1TB
Which can i replace and with what (i think model) to play it without lag and spikes?
CPU and GPU are the main issues behind low frames. RAM isn’t as bad but having 16GB could potentially help. Motherboard probably won’t do much but you need to make sure you have a more up to date one that won’t bottle neck any other components. Hard drive could be an issue if it’s old and is slow. and NVME(M.2) or SSD would help with loading times and you might see a slight improvement to frames.
There are thousands of great forums and videos that can better explain what specific hardware you should get depending on what you are wanting to upgrade and their price and most of them will compare between different ones as well so you can get the best value for performance.
Your RAM. 16GB is recommended. Also, check your internet. And see where the server is located. The further you are, the higher your ping.