We have an installation with APM 10.7 and upgrading to 10.8. The installation has 1 MoM and 3 collectors.. with more or less a 70 agents, and in addition I have copied some graphics where you can see the historical metrics by collector, the live metrics, etc.
The question is that we have reviewing the information in the official documentation about "hardware sizing and performance":
Hardware Sizing and Performance (broadcom.com)
.. and it seems that the the resources required are too high, or at least theses resources are much higher than what we currently have in 10.7. So, the question is... does it change so much from 10.7 to 10.8?, or is this table something more like... resources for a higher scenario?
To get a more definitive answer , we would need to know how many metrices and vertices does your APM cluster have.
But as a generally guidance:
For 70 agents, a standalone EM with 16GB ("Collector for APM Agents") should be enough, Webview and even APM DB could go on the same host . So a very simple solution may be sufficient