What is the buffer pool used for?

The buffer pool is an area of random access memory (RAM) where Blueworx Voice Response keeps:

Applications held in memory execute more quickly. The number of applications that can be held in memory at one time depends upon the number of buffers that are available to hold them.

Some of the buffers are allocated to the voice cache. This is used to store voice segments played by PlayPrompt, but not those played by PlayVoiceSegment). You are strongly recommended to use PlayPrompt to increase the responsiveness of your applications. Use PlayVoiceSegment only for rarely-heard or lengthy voice segments, in situations where the caller is likely to be prepared for a slower response at first.

Note that voice messages are not stored in the voice cache.