Sounds pretty solid for an emulation machine! Surprised to see that SEGA Rally 2 runs great on Dreamcast since that should be on WinCE (which was notoriously heavier to emulate years ago, but no idea how much that has improved since haven't tested that version again), and its good to hear that at least most Gamecube/Saturn stuff can be handled well in it, though not strange that some games are way more taxing than others. And its still feels ridiculous that PS2 on devices like this is a possible idea, but I guess it will take more development time...and beefier machines.
Also Doom on Duckstation probably looks weird because of the rendering style that game has (no idea if it can be improved with Software renderer or Hardware renderer; haven't tried it myself) but probably can find a native alternative to run the original Doom on it lol
I remember being an angry kid when I found out my Core 2 Duo couldn't handle PS2, after a while I got used to it... Now I'm playing PS2 on a device this small.
So weird man haha
And yeah, I found Rally 2 to run well despite being WinCE practically everywhere I've tried it on. It's probably not perfect but it's full speed, so that's what matters. Other WinCE games might not do so well.
And yeah about Doom, I'm already playing it through RetroArch, I think it uses PrBoom there. Runs fine, but PS1 Doom is so interesting, one of my favourite ports.
It's a shame but eh, what can ya do? :P