Difference between OSX and Windows | LabJack

Difference between OSX and Windows

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mexander's picture
Difference between OSX and Windows


We're using a labjack U3-HV to trigger a recording device and provide timing signals. On the mac (OSX 10.10.5), signals last approximately 0.4 ms, but on our Windows 7 machine, they last almost 10x as long, about 3 ms. Both are using the same identical python code, and use the same labjack. Is there a reason for the lag on the Windows machine, and something that can be done, or is it driver related? Thanks in advance.

Relevant python code:

d = u3.U3()

def send_trigger():



LabJack Support
labjack support's picture
The driver/code shouldn't be

The driver/code shouldn't be the difference. The speed difference is most likely related to USB host speeds. We document average speeds as about 0.6 ms (USB high-high) or 4.0 ms (USB Other), so similar to your 0.4 ms and 3.0 ms speeds:


Note that speeds can vary from computer to computer, and your times are a little better then the documented average times.

To get closer to 0.6 on your Windows machine, try connecting your U3 to a USB2 hub and have the hub connected to your USB2 host (your computer's USB port). We find that helps 4.0 ms times speed up to 0.6 speeds. This is documented in the link provided above.