Bet Angel can retrieve market information/data from the Betfair in two ways.
Polling
Traditionally this has been done by Polling which is where Bet Angel calls the exchange to request the latest market information like prices and money waiting to be matched etc. It's up to each user to set the frequency they wish to 'poll' for this information at. This is done by setting the 'Refresh' rate on the main Bet Angel page. You can chose to refresh anywhere from every 200ms up to 1min.
Streaming
In 2016 Betfair introduced streaming which means market changes are now pushed directly from Betfair to your PC, so you'll be able to receive more updates per second than using the traditional 'polling' method of API usage.
With streaming enabled you will be able to retrieve the latest market information as quick as every 20ms, which is 10 times faster than can be done by 'Polling', you can also set the refresh to Refresh Every 'Update' which will cause the screen to be updated as soon as new information arrives on the data stream from Betfair,
You can switch between either option in the Communications area in the main settings.
Note: If you are on a less active market and no data arrives within 500ms then the market is refreshed anyway to keep charts and Servants ticking over. using 'Update' as your refresh rate will save a few milliseconds over the 20ms rate on an active market and save some CPU load on a less active market.
At 20ms the ladder can get a bit mesmerising so you may wish to run the main screen a bit slower, however even if slowing your main trading page down you still can keep 'Guardian' refreshing at full speed as the biggest advantage of streaming is when using Automation in Guardian, enabling you to run rules against dozens of markets every second.
