This is almost certainly normal. EPOProductSettingValues can have a very large rowcount - it contains every single setting for each product installed on every machine. Please do not, under any circumstances, try to modify this table.
OUIs contains a list of vendor MAC addresses, and should essentially be static. We update the contents of this table occasionally but it should stay pretty much the same.
EPOServerEvents contains details of things like pull tasks and replication tasks, as far as I know.