A guide was just posted that showed how to upgrade your Dreamcast’s RAM from 16MB to 32MB. At the moment, only homebrew and emulators can utilize the extra RAM, not original games: https://tsowell.github.io/2020/06/21/dreamcast-32mb-ram-upgrade.html
There’s already BIOS flashers available that will allow homebrew to see the extra RAM, but the real question on people’s minds is: Will this eventually lead to Naomi roms supported on Dreamcast? It’s being speculated that Naomi has twice the VRAM as the Dreamcast and quadruple the sound RAM, just upgrading the RAM to 32MB won’t be enough. I’ll still keep my fingers crossed, as a full Naomi setup is expensive and can be complicated to use.
If you’re looking for more info, it’s currently being discussed in this thread: https://www.dreamcast-talk.com/forum/viewtopic.php?f=2&t=13039
…and if you’d like more info on awesome Dreamcast mods, please check out the following videos: