From their forums:
You might have noticed a performance decrease within the last few releases or finally when updating to Mac OS X 10.6 Snow Leopard.
If you did, try this:
* Go to VLC's preferences
* Click on "All" at the bottom of the window
* Navigate to "Input/Codecs" -> "Access modules" -> "MMap"
* Activate "Use file memory mapping"
* Save the settings and restart VLC.
Afterwards, VLC should perform as expected. We will enable this setting by default in future releases of VLC for Mac OS X.
http://forum.videolan.org/viewtopic.php?f=12&t=65662
You might have noticed a performance decrease within the last few releases or finally when updating to Mac OS X 10.6 Snow Leopard.
If you did, try this:
* Go to VLC's preferences
* Click on "All" at the bottom of the window
* Navigate to "Input/Codecs" -> "Access modules" -> "MMap"
* Activate "Use file memory mapping"
* Save the settings and restart VLC.
Afterwards, VLC should perform as expected. We will enable this setting by default in future releases of VLC for Mac OS X.
http://forum.videolan.org/viewtopic.php?f=12&t=65662