Hi notProngs, As this issue only occurs for a relatively short period of 5-20 minutes, I have a few questions.
- Can you confirm if you are using the same modem or a new one provided by Telstra?
- Do you notice this speed issue on all devices at the same time and are those devices connected via WiFi or Ethernet cable to the modem?
- Are there any devices that are turned on around the time that you experience this issue?
- Have you checked all devices (ie: computers, tablets, smart phones, gaming consoles) for cloud back up services, security software updates etc?
- Shelly