What happens on the day that google updates the PR?

I know the day that Google updates the PageRank, if you increase the PR your site happens to have more relevance and so on.
But I wonder if on that day to upgrade, it rises in the SERPs, or this happens before and after as well, regardless of Pagerank

 

The change of the Google toolbar PR has no direct effect on the SERPs. The toolbar PR number is a 5+ month old number. Google's internal numbers are updated all the time. Consequently, an update today will have no effect on today's SERPs.

 

Thanks!
I think it takes a lot to update the serps, domain which have enough quantity of quality backlinks and Tehama not update content internal constant, because my site did not update for over a month in SERPs

 

Nothing happens when there is a PR update, except a new thread starts with 78 responses talking about what their page rank actually did on their own site.

 

that's totally different.. you can have PR0 but still rank well..

 

Before, when PR updates, SERP changes (usually called Google Dance) first then backlinks update too. SERP rankings will slowly back to normal after few weeks.