How to speed up the Spectrum analyzer in simulink (rule of thump)

I'd like to ask for advice how to correctly set (use) a Spectrum Analyzer. I have a Simulink+SimScape simulation in continous time domain where my signals live. These signals which I am intereset in are about 100kHz frequency area (+/-20kHz)... How should I set up (configure) the Spectrum Analyzer to be "responsive" - as of now sampling to many points and simulation are slow-down, and quite time to refresh.

What "sampler" should be connected prior Spectrum Analyzer, or it has same internal sampling set by "Sampling rate (Sample/Update)"?

Should I combine with pre-connected "ZOH" on this signal under test?

Thank you helping me out.