Empirical studies have shown that human beings cannot normally perceive changes in numeric data (e.g. price movements) occurring more frequently than once every 200ms.
Consequently for applications that have a human as their primary user, a useful rule of thumb is that Stop-The-World (STW) pause of 200ms or under is usually of no concern. Some applications (e.g. streaming video) need lower GC jitter than this, but many GUI applications will not.
Voilà, pas la peine de tuer la machine à rafraichir trop souvent, 5Hz ça suffit.