I'm a recent (?) victim of Dassault's depreciation of the free version of DraftSight looking for a free alternative for my home 2d drafting needs.
In spelunking around, I came across LibreCAD, and it looked good. Very good. Downloaded the latest copy and installed it and. Oh my.
This thing is slow. Very slow. Too slow to actually be useful for anything. Admittedly I'm running it on an old Dell Precision M6400 workstation, but this machine is serviceable for many other engineering software packages. This machine ran DraftSight v2018 very nicely.
I opened the largest dwg file I have (5,285 kb) and it takes upward of 10s to open. Autozoom is another 5s-10s. Attempting to pan around by pressing down the scroll wheel results in literally a white screen.
It is true that LibreCAD is very slow on large drawings. It probably has not been designed for that (architectural drawings?). The V3 version in development is said to adress this issue with a new core. But is not to be expected in next time.