Are both original Xbox emulators built off of QEMU (Xemu is a fork of XQEMU). I've only used Xemu, but performance was pretty good for the games I tried on it (it doesn't have a way to upscale rendering yet though).
MegaDeKay
Good news! Upscaling is in work but buggy right now.
https://xemu.app/
https://xqemu.com/
Are both original Xbox emulators built off of QEMU (Xemu is a fork of XQEMU). I've only used Xemu, but performance was pretty good for the games I tried on it (it doesn't have a way to upscale rendering yet though).