Sometimes your ISP may oversell your node, leading to slower connections. Sometimes it might be the time of the day - too many people may be online. It could be your router or your computer's NIC.
If you open CMD by clicking Windows key + R, then typing CMD and press enter, then type "tracert 8.8.8.8"
That will show the ping to each hop to get to 8.8.8.8
You might notice some are slow, or everything might look fine. If that works fine, you can try running tracert on the specific CS server you are connecting to, it might just be the server.