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The software or device appears to be interfering with the performance of my PC or interfering with other attached USB devices.


Under normal operation, the logic software and device should not interfere with other applications or devices on the system, with a few exceptions:

  • The software can consume a lot of memory after recording for long captures or at high sample rates. When a computer runs low on memory, all applications may respond slower as the system needs to constantly swap memory to and from the page file. Watch the memory usage of the software to see when this happens. On machines with slower disk access, the OS's caching process may make other applications appear completely unresponsive - sometimes including the OS and even the mouse cursor. If you notice this, monitor the memory consumption during the next capture, and end the capture early with the stop button before the Logic software consumes more than 90% of the installed RAM. Also make sure you are using the lowest analog sample rate appropriate for your application.
  • When sampling, the device can use between 0% and 100% of effective USB bandwidth. However, Logic uses a low-priority USB transfer mode, called bulk. Devices like USB mice or sound cards use a higher priority transfer mode called "isochronous". These devices should not be affected by Logic. USB flash drives, hard drives, or other devices however will be negatively impacted, but only when Logic is actively sampling.
  • When sampling analog channels, or high density digital channels, the Logic software may consume much or most of the CPU. This may cause other applications to respond slower. This should only be temporary and the CPU usage should return to normal once the capture and data processing is complete.

Recommended solutions to PC slow down

If the PC is slowing down due to high memory consumption and caching, try the following:

  • Make sure that if you are recording analog, that you are using the lowest sample rate acceptable for your signal
  • Disable all channels you're not using.
  • If you're using one or more analyzers, remove them during the capture. Once the capture is complete, save the capture, and then apply the analyzer.
  • If you're using more than 1 analyzer, try only using one at a time. Saving logic setups are an easy way to change out analyzers and settings.
  • Record for shorter time spans. See information about capture length here: What is the maximum sample buffer size?
  • If you're recording analog, turn off the up-sample option in the software preferences. This causes a very minor visual downgrade in the analog data, but reduces analog memory usage by 3x.
  • Brake up long captures into a series of short captures. Consider automating this: How to take long captures that can't fit into memory at all at once? How do I use the Socket API?
  • Buy more RAM. A LOT more RAM.

More serious issues

Under normal operation, you should not experience any more issues. However, if you notice a correlation between issues with either software performance or other USB devices while the Logic software is running or the logic analyzer is connected, check the following:

  • In task manager, watch the CPU usage and memory usage of the Logic software. is it abnormally high?
  • Remove Logic from the USB port - did the problem go away? Test logic on other USB ports and on other USB hubs. There could be an issue with interference from other USB devices, if those devices do not properly handle USB traffic.
  • Close the software and re-open it. Did the performance of other applications return to normal?

If you suspect that there is a bug with the Logic software, or have found a way to reliably reproduce the issue you are experiencing, please review this article and then report a bug: The software has crashed, or I have discovered a bug.

Tags: My computer freezes when using the Logic software.

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