Im still learng FCP and at the moment Im editing HQ1080 24p footage in a 24p timeline in FCP 6.0.2 on a Macbook Pro , Specs are 2.33GHz Intel Core 2 Duo, Memory 2GB 667 MHz DDR2 SDRAM

Its a short documentary on an artist friend of mine. There are a few slow zoom shots of some of his work that I have been trying to speed up by adjusting speed from 100% to 200%. When I try to play the sped up footage back, it stalls and a warning pops up telling me that 1 or more frames were dropped during playback, it then gives a list of things to adjust so it doesn't happen again.

-Turn of"unlimited RT" (Which I had already done)

-Lowering your compression data rate.( Dont know how to do that, and will it effect quality if I do?)

-Closing open sequences. (Theres only about seven short shots on the timeline adding up to about 2 minutes)

-Lowering the preferences for real-time audio tracks. (there is no audio yet)

-Increaasing the speed of your system and/ or disk drive and/ or network connection. (In other words buy a new computer?)

Has anyone else experienced this? Is it because of the size of the data? Should I be adjusting the speed in some other way? Im sorry if these are dumb questions I should be figuring out myself- and I am trying to do that. Any advice would be greatly appreciated. Thanks.

are you rendering the sequence?

The 1080 24 sequences drop into the timeline and don't seem to need to be rendered, only "other than 1080 24p footage" when dragged to timeline or 1080 24p footage that ive altered like dissolving into other shots etc seems to need rendering.
With the sped up footage up it doesn't seem to need rendering. It starts to playback then stops every few frames to warn me about dropped frames, i click ok, it rolls again for a few frames and same thing happens again. Is that normal?

Select the clip and render it - it should play smoothly.

It worked! I had been pressing Apple R after highlighting the clip and when nothing happened had assumed it was already rendered. I hadn't realized the clips under the green lines were unrendered sequences and that you had to go into the menu bar up top to sort that out.
Plays smooth now. Thanks Eric.

Alexander, check your Sequence/Render All and Sequence/Render Selection settings. Make sure you have the appropriate render states (colors) selected.

Thanks Craig, I've done that now.