3X IR not same as native resolution?

[Qaazavaca Qaanic]

I have a 1920x1080 display. When I select auto-screen-size, I get a perfectly-sharp but sharply-aliased picture with EFB defects (MKWii bloom). When I select auto(multiple) or 3x IR, I get blurry aliasing and slowdown, but no EFB copy defects. The blurriness persists with "resize window" with fullscreen disabled.
Interestingly, the resize window option generates windows smaller than my 1080p for both 3x and 4x IR.
RMCE01-09.png is the auto.
RMCE01-10.png is the 3x, if you can't tell from the EFB copy defects.

[JMC47]

The bloom softens the image, the reason it looks clearer is because the bloom is glitched. At least, that's my guess.

[Qaazavaca Qaanic]

Wrong. When I disable EFB copies, the blurry-edge problem is still present, even after the bloom is gone. (along with overly dark everything, and that black box in the corner.
I think the reason AutoIR is buggy is because it is a hack designed to work with all IRs and has some off-by-one errors, et cetera, that cause the bloom to be copied from too high, or rendered too low. The blur pass stretches the glitch line into a fringe of glitchiness across the top of the screen.

That does not explain why 3xIR has that weird blurring effect that I think results from rendering then stretching to my screen resolution, meaning it's rendered at the wrong resolution. Does Mario Kart Wii have any trickery that renders the image at a reduced resolution then stretches it somehow?

Edit: By the colors of the road, it is clear that the 3x is internally rendered at a different resolution, but whether 3xIR is greater than or less than 1920x1080, I can't figure out.

[neobrain]

The filenames on the images are lost and I have no idea which one is meant to refer to which IR (I could probably figure it out from your description, but I'd rather have you tell me).

That said, I have a theory of what's going on, but I really would like confidence on which image refers to what, first...

[Qaazavaca Qaanic]

3x https://forums.dolphin-emu.org/attachment.php?aid=10455
Auto https://forums.dolphin-emu.org/attachment.php?aid=10456
3x EFB disabled https://forums.dolphin-emu.org/attachment.php?aid=10463
Auto EFB disabled https://forums.dolphin-emu.org/attachment.php?aid=10464

[neobrain]

Do you have the widescreen hack enabled and/or did you force a custom aspect ratio?

[Qaazavaca Qaanic]

No and no. BTW it's OpenGL.

[Qaazavaca Qaanic]

Bümpıty bümp.

[Qaazavaca Qaanic]

Anything?