Many Dell XPS M1530 laptops are shipped with a DVD-rom that (appears to) have a bug in them. This bug causes the BIOS to use extra long time to check the device before continuing boot. In some cases the boot time is some times up to minutes just for the BIOS to perform it`s checks. And that is when the quick boot is enabled.
The “fix” for this issue is to simply disable the DVD-rom in the BIOS completely (Simply set the Module Bay Device to off). As of now (june 2010), a fix is not available for this issue.
Edit: And yes, this does work for me! My boot time went from 2-4 minutes to seconds!