Periodically, market data servers send Investor/RT a time of day notification to ensure that the user's computer clock is in sync with the server. When the time of day sent by the server, which we consider authoritative, is offset more than a second or two from the current time of day on your computer clock, this message will appear. It indicates a condition that should be corrected. It is important that your computer clock be set to the exact hour/minute/second every day. Investor/RT monitors the time stamps of incoming trades comparing them with the computer clock to see how much latency there is between the occurrence of a trade and time Investor/RT receives it. Obviously if your computer clock is say 5 seconds fast, Investor/RT may incorrectlly determine that I/RT is falling behind real-time data reception. Similarly, if your computer clock is 5 seconds slow, then Investor/RT could incorrectly determine that the data feed is current when it fact it is up to 5 seconds behind in actually. Synchronizing your computer clock daily with a time server is the soluiton. The Clock Offet messages are just a reminder that your clock appears to be offset more than a few seconds from the server.
To correct this, Windows users double-click on the clock in the task bar to bring up the Date and Time Properties window and, under "Additional Settings" click on "Sync Now" to update the computer clock. The update takes approximately a few seconds to complete.
To permanently fix the issue, we strongly recommend using a free PC clock synchronizer utility. NetTime is among the most trusted applications and will keep your PC clock synchronised.
Why is my PC clock drifting ?
- The PC clock is not very precise : Your PC counts time with a small quartz crystal on the motherboard. These crystals are cheap and not perfect. A typical error is about 20 to 50 parts per million, which means the clock can gain or lose about 1 to 4 seconds per day. After a week without a sync, that adds up to many seconds.
- Windows syncs too rarely. By default, Windows checks the time with an internet server only about once every 7 days. Between two checks, nothing corrects the drift. This is the main reason you see a few seconds of delay.