Sorry about the delayed response.
The Squeezebox Server is an open-source software whose active development in the slimdevices forums benefits our OS and every user of Max2Play. If you have specific questions on the technology behind the Logitech Media Server, please consult these forums: forums.slimdevices.com/
You can also look at these tips to optimize your sd card speed: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=144493
Nonetheless, a search task is most likely never split between cores and your list of 100.000 songs might be the critical mass for the Pi. You can consult the slimdevices forums on devices with more powerful single cores.