Ram compatible

[EmThanhGiauTen]

Laptop: HP Laptop 15-dy2091wm (Product Number 491D1UA#ABA, System Board ID 87FE)
CPU: 11th Gen Intel Core i3-1115G4 @ 3.00GHz
BIOS: AMI F.33

RAM:

Original: 1x 16GB stick from HP — works fine, boots normally
Adding: HyperX Impact HX424S14IBK2/32 kit — 2x16GB DDR4-2400 CL14, 2Rx8 (dual-rank), 1.2V (manufactured ~2016)
Problem:
Each HyperX stick boots fine alone, in either slot — tested all 4 single-stick combinations individually, all pass. With both HyperX sticks installed together, the laptop powers on (fans spin, lights on) but the screen stays black and never completes POST. The Caps Lock LED blinks a number of times, pauses, then repeats the pattern (blink count: [fill in here]).

Troubleshooting already tried:

Full power drain (unplug charger, hold power button 30 sec) before testing both sticks together
Reseated both sticks
Waited several minutes in case of memory training on first boot
Checked BIOS Main/Security/Configuration/Boot Options — no memory-specific settings exist on this model
Confirmed via CPU spec that the platform supports well above 32GB
Question:
Each stick works solo but the pair fails to POST together. Is this a known incompatibility between this HyperX kit and the HP 15-dy2000 series (older dual-rank CL14 modules vs. a newer platform), or could it be a BIOS/motherboard-side dual-channel limitation? Would a BIOS update from F.33 realistically fix this, or is the safer route a modern DDR4-3200 kit?

[Paul_Tikkanen]

You need to install DDR4-2400 with the standard CL specs that the original HP memory chip has, which is CL17.

Most if not all HP consumer class, non-gaming notebooks use memory with standard timing specs.

The BIOS can't negotiate the different timings.

I'm actually quite surprised the CL 14 memory worked at all.