This is possible because the HD 4000 family uses the ancient driver interface that didn't have a low resolution check. With newer cards, you can't add low resolution on stock drivers (unless you use this method).
Very interesting.
Do you which model is the most powerful and also uses that "ancient driver"?, HD 4890? HD 4830?
I just wanna get the best model out there, without the need of restarting into Test Mode.
Also apologies for necroposting, just thought the answer would be useful for peopel who are in the same boat as me.
HD4XXX cards are a massive PITA to get working right with CRT_emudriver - it is much easier to install with the HD5XXX+ cards that support EDID.
They are also literally massive compared to cards a bit newer like the HD6XXX cards, with which CRT_emulator installs always seem to go smoothly with a few clicks.
While you can't remove the test mode text, it is possible to edit it so that nothing is visible, or to at least change the message to something more appropriate.