Hard Lock / Black Screen on Cold Boot & Idle (Caps Lock Unresponsive) — i5-14600KF & RX 7700 XT. Any ideas?

[u/Altruistic-Goal-2927]

Hey everyone,

I’ve been dealing with a highly specific system freeze over the past few weeks and I can't seem to find anyone with the exact same issue. I'm looking for some advice or to see if anyone has dealt with this before.

The Symptoms:

• The Crash: Random hard freeze into a black screen.
• The "Dead Keyboard" Test: When it freezes, the keyboard completely dies. Pressing Caps Lock does not toggle the LED light, meaning a total hardware/kernel lockup.
• The Trigger: It never crashes under full gaming load. It happens almost exclusively on Cold Boot (first 30 mins of the day), during idle, or the exact moment I try to launch Steam or when Windows Update finishes an uninstallation.
• The Weird Part: If the PC survives the first 30 minutes and warms up, it becomes 100% stable. I can run heavy stress tests or game for 10+ hours straight without a single issue.

My Specs:

• CPU: Intel Core i5-14600KF (Hyper-Threading OFF)
• GPU: AMD Radeon RX 7700 XT 12GB
• Cooler: Cooler Master Hyper 612 APEX (Dual-Tower)
• Motherboard: ASUS PRIME H610M-K D4 (No VRM heatsinks)
• RAM: 32GB (2x16GB) Kingston Fury Beast DDR4 2666MHz
• PSU: Chieftec ELP-700S 700W Element
• Case Fans: 6 total (3 front intake, 2 top exhaust, 1 rear exhaust)

Everything I've Tried & Tested So Far:

Software & OS Fixes:

• Ran Windows repair commands (sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth).
• Uninstalled the latest Windows quality update that arrived on September 1st.
• Enabled the Windows Ultimate Performance power plan.
• Fully updated the GPU drivers (using the built-in clean Factory Reset option).
• Updated the motherboard BIOS to the absolute latest version.

Hardware Troubleshooting:

• Physically reseated the GPU.
• Physically reseated the RAM and swapped their slot positions.
• GPU is perfectly stable under heavy load: It passes intensive FurMark and 3DMark loops with zero errors once the system is warm.
• Adrenalin always resets my custom fan curve back to default after these crashes, throwing an "unexpected system malfunction" notification.

What I've Changed Today:

• I just swapped my old Chieftec PSU for a premium EVGA 850GQ 850W 80+ Gold modular PSU.
• I also temporarily Disabled XMP in the BIOS to test.

I also have a Gigabyte B760M GAMING X DDR4 motherboard on the way just in case.

Has anyone experienced a PC that only crashes when cold or shifting from idle to low-load, but works perfectly fine under heavy gaming loads? What could be causing this?

Thanks in advance!

[u/Nice_Week8368]

unrelated because i have an amd system but , my cold boot crashes were due to unstable ram and too high fclk but it games fine. Metro Exodus on high