So I have been encountering this issue when my laptop's performance dropped whenever Synapse was running in the background due to high CPU usage and overheat. It was so bad that LoL framerate dropped to around 10fps. I couldn't just turn off Synapse either because Razer devices can't save RGB settings on the onboard memory and without Synapse constantly running, my mouse wouldn't work as intended. So after contacting Razer support team and having a conversation with them for a while, we managed to resolve the issue.

Here are some steps you could try:

• Update Synapse to the latest version (for now it's 3.8.831.90619)

• Run DISM and SFC

1. Open Command Prompt

2. Type: DISM.exe /Online /Cleanup-image /Restorehealth

3. Wait for it to finish

4. Type: sfc /scannow

5. Wait for it to finish

• Run CHKDSK

1. Open Command Prompt

2. Type: chkdsk /f /r

• Delete TEMP folders

1. Open Run by right-clicking Start and choosing it from the menu

2. Type %temp% in the Run window and click OK

3. When in File Explorer in the TEMP folder, select all files by pressing Ctrl + A keys

4. Click Delete

• Razer Driver Cleanup Tool

1. Uninstall Synapse 3

2. If possible, unplug all Razer devices

3. Reboot the system

4. Download the Razer Driver Clean Up Tool: https://rzr.to/7c7Za

5. Unzip and run the CleanupRazerDrivers.exe as Administrator

6. The window will close on its own. When it does, reboot the system again

7. Install Synapse 3

8. Plug in Razer devices

9. Update Synapse 3 as needed and reboot system as update requirement

I'm not sure which particular step resolved the issue, but after performing all these steps, Synapse stopped causing heat and lag.

I wanted to share this so you guys won't have to chat with the support team on email for weeks just to get the same instructons. I hope this will help many people.