I recently upgraded to 10.13 High Sierra, and one thing I noticed almost immediately was that the downloads dialog in Safari was incredibly slow. When I click the icon next to the address bar which should show the recent downloads, it takes about 5 seconds to show, during which the browser is unresponsive. After clicking somewhere else to dismiss the recent downloads box, the browser is totally unresponsive for another three seconds or so. In addition to this, when I click a link to start downloading something, the browser is unresponsive for a few seconds, and also upon finishing a download there are a few seconds of unresponsiveness.
Note that this is not about the speed of the downloads themselves. I don't have any browser extensions installed (I used to have the Zotero extension installed, but that broke after upgrading to 10.13).
Does anyone know of a solution to this? I access downloads a lot (for academic papers), and this is driving me mental.