Why does the laptop not start after replacing the OP?

Question

Dell

Good afternoon!
Laptop Dell Latitude 5300. Hynix HMA81GS6DJR8N-VK OP (DDR4, 8GB, 2666, PC21300, CL19, no ECC, 1.2V) was included.
I decided to upgrade by purchasing two Kingston Fury KF426S15IB/8 OP sticks (DDR4, 8GB, 2666, PC21300, CL15, no ECC, 1.2V). After installation, the laptop does not start. When you try to start, it signals that the OP is not detected (three white signals, then two yellow ones).
At the same time, the laptop does not start in the configurations:
1.1 Two Kingston brackets
1.2 One Kingston bracket
1.3 Hyinx in slot A - Kingston in slot B
And it starts up:
2.1 One Hynix bracket (respectively, as from the factory)
2.2 Kingston in slot A - Hynix in slot B ( while in windows it shows 16 GB and everything works)
Can anyone come across this? Memory differs in timings (CL15 and CL19). It is not clear why it starts working in configuration 2.2. Is there any way to fix it or just replace the OP?

Answer 1

Datasheet on a laptop

maximum 2 to 16
If I understood correctly, you had one bar for 8
Why does it start when there is one native and the second is new

You can install RAM with different timings, as well as strips of different volume or frequency. In this case, the speeds are also equalized by the slowest element. If one bar has CL15 delays, and the second one has CL17 delays, then they will work together with CL17 timings. As with a frequency mismatch, if the computer does not start with two bars, you need to manually reduce the frequency and increase the delays in the UEFI BIOS settings.

In general, the advice is to manually correct the memory parameters in the BIOS for the new timing, then I think it will start.
But there is a risk when resetting the BIOS, you will not start.
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