These particular applications are supposed to be well written, one is Dukascopy's (big fat banking thieves, most definitely have money for software), one is Oanda's (little sneaky broker thieves, also have money for software), although I also hate to use them as they really are resource-hungry. The software I actually use takes like 100-300 MB RAM and 5-10% on same CPU, but is x86 dependent.
With 2 GB of RAM would the board really need swap? Even if intended to run 500+ MB demanding software? I have 3 and 4 GB RAM desktops running GNOME and KDE (I would probably put Xfce or LXDE on the SBC) and I've never used swap on them.
By "downloading a movie" I meant torrents (this is Bulgaria, we are illegal AF), which by the way might come close to the case for random 16 MB reads/writes from the eMMC tests, some torrents downloading at some speeds with some torrent client caching settings at least.