Oil Spill Detection Processing time

i am using the Oil Spill Detection tool (after subsetting (only VV-Channel) and Speckle filtering).
The resulting Frame is about 7000x10000 Pixels.
I am using the following settings:
Background Window Size: 600
Threshold Shift: 2.0
Minimum Cluster Size: 0.1
However the processing is extremly slow with an Ubuntu machine with 30GB Memory and 8 CPU.
I adjusted the configuration to
default_options="–branding snap --locale en_GB -J-Xmx28504m -J-Xms4096m -J-XX:+AggressiveOpts -J-Xverify:none -J-Dnetbeans.mainclass=org.esa.snap.main.Main -J-Dsun.java2d.noddraw=true -J-Dsun.awt.nopixfmt=true -J-Dsun.java2d.dpiaware=false "

I tried various different settings, however processing is always stuck at
about 1% for at least 1 hour (then i abort).
The CPU utilisation is only at 25% and Memory Usage abotu 2.6GB.

Do you have any ideas how to increase the performance, or is this the expected behaviour?
I used the settings for oil spill detection based on this video by RUS: https://www.youtube.com/watch?v=Jm1kIZBhJK0