The attached example renders two grayscale ramp textures, the upper one with 8 bits per channel and the lower one with 16 bit per channel (the Widget set the texture format to GL_RGB10_A2).

On Windows, when compiling this with Qt 6.2.7 (MSVC 2019) you will see that the 16bpc channel texture has much less bending and is smoother than the the other one (only notable on monitors which are able to display 10bpc).

With Qt 6.9.2 (MSVC 2022) both textures have the same bending.

As far as I could trace back this, the problem stems from the QRhi changes. I tried to change some places where a hardcoded QRhiTexture::RGBA8 was used and also set another QImage format in the QWindowsBackingStore and QBackingStoreDefaultCompositor but without success.

This is probably also broken in earlier "post-QRhi" versions.