DDR3 bar that only works with built-in vidyuhi. Why?

Question

Video cards

The DDR3-1333 RAM stick behaves strangely. If the PC has a discrete graphics card, then the PC does not start, as if the memory is not working. But if you turn on the built-in video card, it works properly and the memory tests pass.
Tested under Windows 10 and Linux Lubuntu 18. Memory for embedding was set to 256MB and 32MB.

I haven't run video tests, but I'm already planning to.

Tell me why is this happening?

Answer 1

If the failed area is used for video memory (well, so lucky), then there may be artifacts (including subtle ones), but it may well not freeze anything. With a discrete video card, the same failed memory area may be used for the operating system - in this case, freezes, BSODs, etc. very likely.