Due to LabView timeslicing issues, special handling of the LL_USB.INI file (in your Windows directory) is required for optimum performance. Always set: StackedIrpCntOverride = 40 ProcessPriorityBoost = 1 The following LL_USB.INI entry will need adjusting for your PC and operating system: ScanSystemBoostLevel You can experiment until you find the best setting. Our development PC responded best with: ScanSystemBoostLevel = 4 The smallest possible number is recommended and a number higher than 6 is not recommended. Experiment with values from 0 to 6 until the maximum scans/sec are achieved.