First, if you’re using the paper trading version of thinkorswim, the default is to provide delayed data. You may want to contact thinkorswim support to see if they can switch you to real-time data on your paper account, as well as verify there are no delays on your real account (there shouldn’t be).
If you’re confident that you’re using non-delayed data, the next thing to check is your Calculations setting in the thinkorswim Application Settings. You can find these settings on your Main thinkorswim window in the upper right corner under the Setup menu. Select Application Settings..., then choose Calculations from the choices on the left.
The following image shows the choices that you have under the Analyze data recalculation menu. Many users will have “Steady” as the choice, which means you could experience update delays as much as 30 seconds. If you choose the Real-time option, there’s no delay, but it will put more demands on your computer to keep up with the data stream. Many users prefer the “Fast” setting, which has a max delay of 5 seconds between updates, which can provide a good balance of faster updates without too much pc and internet demand. Experiment with what works best for your own computer and internet connection.