hpst Meaning when I go to a full screen "console" on Ubuntu derivatives with CTRL+ALT+F1 etc am I getting a true console or an X11 rendered full size terminal emulator?
Normally you would get the same video mode when you switch. So outside Xorg but no video mode change at all. Because of the "Kernel Modesetting" feature: The video mode is chosen by the Linux Kernel at some time during boot. You get a true console but the modesetting driver is already loaded and running. You can prevent modesetting by putting "nomodeset" as Kernel parameter at the end of the "linux ..." line in your grub entry. Then you will get a low-res text console without any specialized video driver. You may find this mode similar to BIOS boot text screens, MS-DOS command line or Windows setup which are pretty much "known-good". Nothing fancy, no acceleration, just a basic standardized video mode that all cards understand. Not sure how the exact term for this mode is called - Standard VGA or VESA VGA? Something like that.
If you use the NVIDIA proprietary driver, it only supports Xorg, so it will switch to this "known-good" video mode when you press that key combination. But most other drivers depend on Kernel modesetting nowadays and will use it for displaying the console.
When the image appears instantly upon switching without a black screen in between, the video mode hasn't changed at all. Or the graphics card does upscaling to the monitor's native resolution. Not sure if all modern cards do this. The two that I have are unusable cards and they both do this. (ATI Radeon HD5450 and NVIDIA Geforce GT 710).