&gt; <i>In other words, cache misses are taken into account to the extent that the model above is reflective of your workload and hw environment.</i><p>Fair enough. Though <i>I think</i> they have in mind cache misses in the sense of page faults here? - i.e. &quot;it&#x27;s not in memory - have to read from disk&quot;. (i.e. cache as in Postgres internal cache (+ OS filesystem cache, actually&#x2F;IIRC). The variable name `random_page_cost` seems to suggest this (load a memory page into memory - from disk).<p>Whereas I had in mind cache as in CPU cache[1] - where sort operation happens which does lots of cache misses (between CPU cache and RAM) - and needs to read from rest of RAM (i.e. random memory access is not uniformly random). It&#x27;s a nice rabbit hole..<p>[1]: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;CPU_cache" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;CPU_cache</a>