Depending on the situation, using PureRenderMixin may be less efficient than an immutable-targeted render mixin as it checks for identity not equality. It&#x27;s easy to hit cases where Immutable collections are equal but not identical (especially when converting from a base state e.g. list.map(func) will create a new list every invocation, but it may create equal lists across invocations).<p>Depending on how often that happens (and thus subsequent extra reconciliations or even re-renders) versus the cost of checking collections for equality (generally O(n), versus O(1) for identity), you may get extra performances from checking for equality.