I always took it for granted all these were just emulators on an ARM-based setup for the simple fact that they perform absolutely horrible compared to even the shittiest, cheapest GOAC clones available. Most GOAC clones have noticeable audio issues like twangy music, volumes on channels being off, etc but every single AT Games product I've tried is distorted to the point you virtually cannot even stomach to listen to it. I've probably played about 10 different flavors of GOAC machines and all are head and shoulders above every AT Games product. Hell, all those that are compatible with real carts (or load ROMs) won't even save games, that's an issue that I've never heard of any other GOAC console having.
I think the poster mentioned has his timeline messed up. Most AT Games clones, especially the Firecore models with SD slots, use ARM processors, and only this newer 80-in-1 classic system uses a GOAC. I owned this exact same one for a short time and it was absolutely horrible, the worst sounding GOAC system I've ever played combined with the worst game compatibility.
[rant begins]
There's a portable clone put out by AT Games that goes under a bunch of different names and is rebranded and distributed in other countries by different manufacturers. It's commonly referred to as a Gopher and has an SD card slot to load ROMs. Seems like the newest version distributed in the US is licensed by Capcom and includes Super Street Fighter II and maybe Mega Man: Wily Wars.
I picked up a cheap knockoff of this a while back that includes like 100 or 200 games instead of the usual 30 plus the usual run of 50 or so garbage Tectoy/AT Games originals. The gameplay on it is HORRIBLE, I mean utter complete rubbish. There is not one single game that doesn't play with either horrid slowdown or an amount of frame skipping that it looks like a slideshow. There is a gigantic difference compared to the real, licensed version.
The handheld itself is made from the same molds and is physically exactly the same at least from the outside. The menus and everything else are the same except the Firecore name is altered to say "Firecord". It also plays MP3s from the SD card which is something the original didn't.
I always assumed that this was just a knockoff using a cheaper, slower ARM processor which is why it works like the original only worse. A simple GOAC system definitely would not behave like that. Plus you'd definitely have to use some additional hardware/software or frontend to allow ROM loading and on top of that a simple GOAC clone couldn't handle MP3 playback.