FYI - you might find this useful if your computer seems to have a bottleneck on the disk throughput.
I was having a horrible time getting rendering to work fast. The first 2% of my 45 minute movie took 10 hours to render. My computer (Intel Duo Core 2) with 4 GB of RAM was gagging on a large AVI file while rendering. The disk utilization measured at 100% for hours while the CPU sat a 1% utilization. In other words, the CPU didn't have any work to do while the disk drive was busy with something else. The problem was that I had created an AVI file from a Flash animation that was over 1,000,000 KB.
I assumed that since there was such high disk utilization I either needed more RAM, a faster disk drive or smaller video files. The fastest (and least expensive) trouble shooting technique was to put a blank 4 GB SD card in the computer and use it for a scratch disk.
To use your SD card as a virtual disk, insert an SD card. Scroll down to the bottom end of the window and find the heading labeled "General Options." Click on the link underneath the "General Options" heading that is labeled "Speed Up My System Using Windows ReadyBoost."
The performance monitor on Windows then showed that the disk utilization was now being shared between drive C: and drive F: (the SD card). The new disk took just enough of the load to allow Premiere to actually work through the big file and move on to the rest of the video files in the project.
Next time, I will render the flash animations with a smaller resulution to get a file size about 500,000 KB or smaller.