I've been using Amarok for years, and don't remember the amount of memory used being so high.

It starts around 632MB (ksysguard, htop reports a slightly higher number) and usually ends up around 812MB after running for a few hours.

Searching doesn't reveal 'normal' usage, but I see numbers like 135MB and 240MB.

I occasionally listen to music, but mostly podcasts.

Is over 600MB unexpected? If it is high, any suggestions for finding out what is causing it?

Based on a post in these forums, I switched from the Gstreamer backend to the VLC backend, but the memory use hasn't changed.

Amarok
Version 2.8.0
Using KDE 4.14.16

Backend Phonon-VLC
phonon-qt4 4.8.3-5
phonon-qt4-vlc 0.8.2-4
phonon-qt5 4.8.3-5
phonon-qt5-vlc 0.8.2-4

Plasma 5.5.4
Qt 5.5.1

Arch Linux 64-bit
Kernel 4.3.3

is that amount the shared memory or the global one? Please keep in mind that in Linux, the more memory you have, the more likely will be assigned to running applications, so looking at the global memory use is not really helpful, we need the values for the shared memory use.
Using Amarok 2.8.90 on Kubuntu 14.10, KDE 4.14.2, phonon backend gstreamer 4.7.80, I have a shared memory use of 50 MB max when running, about 26 MB when idle, total RAM is 8 GB

Mamarok wrote:is that amount the shared memory or the global one?

The RES column in top and htop, the Memory ("real physical memory") column in System Activity. Right now the numbers for Amarok are:

VIRT 3991M
RES 916M
SHR 86192

852,528 K in System Activity

Total RAM is 8GB

so the shared memory is 86 MB, not extremely high. You could eventually reduce that amount by changing the phonon backend.

Do you use 3rd-party scripts? Might be interesting to see if a script can cause a higher RAM usage.