smythie wrote in post #18018394
I'm tihnking it helps to rule out the image processor but not necessarily the CFast card slot and associated specific module(s) and/or processor(s)
Which is why I didn't explicitly say that it ruled out the camera. But you are correct, there are various subsystems within the camera that would need to be ruled out.
So I performed some other tests last night but I couldn't use my flash testing tool on the CFast card.
After formatting in camera, I copied 16GB worth of 1DX raw files to the card with my computer then copied the files off, imported into Lightroom and built standard previews and all the files looked ok.
After formatting in camera I then went outside, with the camera set on Raw+Jpeg, writing to both cards and took a bunch of pictures, copied them off, built standard previews and all files looked ok. I'll keep these files on the card and continue to reimport them to see if they degrade on their own.
If the card does in fact have bad sectors, which I am fairly certain of, I suspect the wear leveling algorithm in the flash controller will cause the errors to show up "randomly" as the controller systematically writes the files to the chips. Most controllers have the ability to mark bad sectors but formatting usually removes that.