Why did two sticks of memory stop working together?

Question

Iron

With two bars, the computer boots up, but the following picture appears on the screen:

With one bar (any) it works fine, in any of the slots.
The voltage of 1.8V is normal, with two bars it does not sag.
Prior to this, for years, the two bars worked together without problems.
DDR2 memory:
1Gb Patriot PSD21G8002 PC2-6400 CL5
1Gb Hynix HYMP112U64CP8-S6 AB-C 1R*8 PC2-6400U-666-12
Palit N61S v2.0 board
No BIOS settings, etc. did not change.
ps The video card is built-in, and there is a suspicion that with two sticks the video memory falls into the area where the addressing is faulty, but I don’t know how to check it.