When burning audio-cd's it is absolutely critical that the data-stream from the harddrive to the CD-writer is as continuous as possible. The CD-writer has an internal memory-buffer to compensate for small gaps, but if your harddrive or your CPU is interrupted for to long, the CD-writer will run out of data. Because the CD-writer cannot wait, this will cause gaps and noise in the music, or in the worst case, it will ruin the entire disc. Buffer Underrun errors are a big problem for cd-burners.

The source of the problem

Windows is a multi-tasking operation system, meaning it can run many programs simultaneously. The CPU, however, can only do one thing at a time. To solve this problem, Windows divides the CPU-time into small slices and gives each running program a short period of time to execute, before the CPU is handed over to the next program. The more programs you run, the smaller each time-slice gets. If the slices are to small, there may not be enough time for the burning-software to fill the buffer on the CD-writer.

Just like the CPU, the harddrive cannot read everything at the same time. If, for example, some antivirus software or a screensaver starts in the middle of your cd-burning-session, the harddrive may get occupied with other things and stop reading CD-data.

The solution

What can I do about prevent those "buffer underrun errors"? There are a few things you should always do before burning audio-cd's:

1. Reboot the computer before you begin to make sure the operating system is completely stable (You never know after running a few games).

2. Terminate all programs but the cd-burning-software including those running in the background.

3. Don't use your CD-writers maximum burnings speed. If your writer can burn at 4x use 2x, if can handle 8x use 4 and so on. This way, the CPU will only have to send half as much data to keep the buffer full.

4. Try increasing the priority of the CD-burning software. You may have to try a few different settings before you find the optimal priority for your system.

5. Burning on the fly is not recommended. If there is a hiccup in the cd-rom you're burning from, you'll get a coaster. Always cache to harddrive before burning. (This is usually an option in your burning-software)
This may not be the final solution for all systems, but it could save some time troubleshooting.

Reference

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by Cariad edited by vkr