The zd1211 and zd1211b in BT4 beta and BT4 PRE are only partially patched. You will inject with speed of maximum 150PPS. If you follow the tutorial your speed will increase to 400-550PPS depending on how far the AP is from your PC.
Following the tutorial is highly recommended to get the most out of your zd1211 device.
PS. proper power level detection has been created for testing. Make sure you try that as well.