Experiment Freezing/Slowing Mid-Presentation

I am currently working on an experiment that occasionally slows and/or Afreezes (or registers as “not responding”) in the midst of the experiment. Occasionally, stimulus that should remain on the screen a max of 2s remains 10-15 seconds. Subsequent stimuli are presented too quickly.

It is not consistent, and I cannot find any pattern to the freezing (i.e. it does not work better the first loading as in http://community.cedrus.com/showthread.php?t=540&highlight=freezing ). When it freezes, pressing ‘esc’ seems to do nothing.

Additional Info:
-The experiment consists of 3 blocks of 500 visual stimuli (taken from 3 stimulus lists). Stimuli are .jpg files, between 40-65kb. Participant response is recorded via SV1 voice key attached by serial port.

-The computer (I have tried on several in my lab) has approx 123GB of free space and 3GB of RAM. The PC runs Windows XP Pro 5.1.

-I am running the latest Superlab Version (4.5)

-Under options, I have selected to load files trial by trial.

Does anyone have any suggestions? Can anyone think of something I am missing? Any help would be much appreciated!

p.s. The only pattern I see is that I struggle to replicate the freeze by myself, but it appears when i have participants in the lab!


i tried running an earlier version (4.0.7b) as suggested in http://community.cedrus.com/showthread.php?t=1022&highlight=freezing and had the same freezing issues.

what do you all think?

Thank you for the information. Do you think you can post your experiment as an Experiment Package to see if we can duplicate the freezing?

Packaged Experiment


I have attempted to attach the packaged experiment (.zip @49MB), but I have received an error message as follows:

“Your submission could not be processed because a security token was
If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.”

Let me know any other way I can submit this to you.


I will contact you via private message regarding this.