you should see a substantial boost by getting more ram. if you can fit 4gb, get it.
even if you only re-install your os you'll probably see a speed boost.
Thanks for the suggestion about increasing RAM. Unfortulately, my laptop only supports 1 GByte max, which is what I have.
Why does an OS re-install help?
isn't everything you do on your computer (including just starting it), at least, somewhat slower than when your computer was new?
One thing is that you could avoid the conversion to flv step if you are targeting flash player 9 and later.
If you export to h264/aac format quicktime files you should be able to load and play them directly rather than having to take the next step and convert to flv. EDIT: You may need to move the moov atom/metadata to the start of the video file instead of the end (google it if this is new)
There are some encoders/converters that use multithreading. I think even virtualdub on windows does.... although I don't use quicktime, I guess I would be surprised if it didn't support it.
In terms of hardware....I have a Qosmio G50 laptop (desktop replacement) which in theory should get closer to the 15 minute mark you target. This is because, in addition to being dual core CPU, it has a separate quad core HD processor which is dedicated to fast and intensive video processing, completely aside from the CPU or GPU. Unfortunately there doesn't seem to be publically available software that leverages the specific chip yet (although some of the pre-installed toshiba apps use it for things like gesture control, indexing video by face and logon face recognition etc). Some of the marketing speak says it should be 5x faster for HD/H.264 encoding than using the CPU alone though....(I'm waiting for the software!)