See this post: viewtopic.php?f=6&t=289
, everything is working as intended
I bet the desktop has a larger screen than the laptop (more resolution, in particular larger or equal to the preview JPEG dimensions stored by your LX5...), which causes the program to fall back to full (and slower) raw decoding because the JPEG preview would not fill the monitor. On the laptop, the preview is "large enough" and gets used for speed.
You can press "R" to initiate a raw conversion on your laptop if you want to pixel-peep, but the program prefers JPEGs because it can display them much quicker. Keep in mind that the JPEG preview size was picked by the camera manufacturer and is supposed to be "enough" to judge the images.
There is a registry setting that let you alter the default behavior, see the aformentionned post, but your laptop may have a slower hard-disk and less CPU/GPU power and memory, so perhaps sticking with the default and just "R" the few ones you really want to pixel-peep is a sensible choice?
Note that this little discrepency only occurs with some compact cameras, current DSLRs often store a 1:1 JPEG preview within raw files and full raw decoding is never required for previewing the files in full resolution.