A few months back I attended a presentation where the speaker went through about 80-90 complicated slides in the first 45 minutes of a one hour session. At that point he said, "I'm going to have to speed up if I'm going to get through all these slides." He went on for another 20 minutes (overrunning his time) and there was no time for discussion or questions.
The audience will not remember all your slides no matter how well your presentation is constructed. You want the audience to ask questions! You want lively discussion! You want to get the audience interested in your work! These goals are more important than getting through every slide. Talking faster does nothing for the audience.
Before your presentation develop a plan for how you will proceed if the time is shortened by either a good discussion or other factors, like the Chairman showing up late. Figure out how you will verbally summarize the parts you're not going to get through and whether there are one or two slides in the omitted sections that really are essential. If you use the technique of "building up" a presentation rather than cutting it down, this task will be easy (see first the earliest tip on this blog).