The empeg design uses PIO (not DMA) for disk data transfers. Doing a lot of consecutive PIO prevents other stuff from running at the same time (there's only one CPU..).

When the player does readahead, it tries to fill nearly all available memory with data before stopping. The more memory. The more available memory, the longer this takes to complete. While the disk reads are happening, the display updates get stalled, and can appear to stutter.

Adding more RAM helps with large databases, extra apps, etc.. but the player software is pretty clueless about it all, and will just try to hog the CPU while filling up the extra RAM with more tunes..

Cheers