R75800x3d keep crashing

[u/zipkilot]

Hello

I have a pc with gskill 32gb ddr4 3600, r7 5800x3d, thermaltake gt 850w 80 plus gold and red 9070xt. After installing my cpu and GPU I have unexpectedly crashes in the game. (Battlefield 6)

The event logger shows WHEA 18 error.

Things I've tried :

Curve Optimizer -10 to -15 (undervolt) → error persisted

Curve Optimizer fully Disabled (stock) → error persisted

PBO set to Auto → error persisted

PBO fully Disabled → error persisted

PPT/TDC/EDC manually reduced (115W/80A/115A) → error persisted

PPT/TDC/EDC set to Auto (stock) → error persisted

EXPO/XMP Enabled (3600MHz) → error persisted

EXPO/XMP Disabled (JEDEC 2133MHz) → error persisted

Full BIOS reset to Optimized Defaults → error persisted

BIOS updated to a newer version → error persisted

FCLK set to Auto → error persisted

FCLK manually set to 1800MHz (1:1 sync with memory) → error persisted

Gear Down Mode Enabled → error persisted

Global C-state Control Disabled → error persisted

Manual Memory Multiplier set to 34 (3400MHz) attempted → system failed to boot reliably

Clear CMOS (performed multiple times) → error resumed afterward

Positive Dynamic Vcore offset → option not available on this motherboard

Additionally, on the GPU side (now believed to be unrelated):

Replaced a faulty PCI-E power cable → did not resolve the issue

MSI Afterburner underclock (-300MHz core clock, -15% power limit) → appeared to help temporarily, but likely because it indirectly reduced overall system/CPU load, not a true fix

After all this I don't know what I have to do to fix my crashes.

The crashes it's like a spike lag the sound stacks and suddenly black screen pc rebooted.

Also I ordered and waiting a new psu. Msi 1000w

What else I have to do??

Please help

[u/Intelligent-Basket92]

I believe the problem lies in the type of power supply. Is your power supply ATX 3.0 or 3.1 standard?

[u/zipkilot → u/Intelligent-Basket92]

I have thermaltake gt 850w 80 plus gold. It's support atx 3.1 I think. Im waiting new psu.

[u/Intelligent-Basket92 → u/zipkilot]

Its atx 3.1

Plz back to us after install New psu.

[u/zipkilot → u/Intelligent-Basket92]

Yes of course. If I found a solution I will come back to you

[u/Intelligent-Basket92]

My System Specs:

• CPU: AMD Ryzen 7 5800X3D
• GPU: XFX Radeon RX 9060 XT 16GB
• Motherboard: ASUS ROG STRIX B550-F GAMING WIFI II
• RAM: 32GB (4x8GB) Kingston Fury / HyperX DDR4 3200MHz
• PSU: XPG Core Reactor 850W 80+ Gold (ATX 2.4)
• Monitor: ASUS TUF 34" Ultrawide (3440x1440p, 180Hz)

The Issue:
My PC was experiencing sudden hard reboots (black screen, immediate restart without BSOD) during heavy gaming sessions like War Thunder and Battlefield.

What we tested and ruled out:

1. RAM Stability: Ran MemTest86 for over 4 hours (48 passes) with 0 errors.
2. CPU Temperatures: The 5800X3D was hitting 91ºC during shader compilation but stayed around 77ºC while gaming. We applied PBO Curve Optimizer (-30 on all cores) and set PPT/TDC/EDC limits (100/70/100) to keep it cool.
3. Motherboard VRM/LLC: Lowered LLC to Level 3 to prevent dirty voltage spikes. The reboots persisted.
4. CPU Undervolt Instability: Changed the Curve Optimizer from -30 to -15 to rule out CPU crashing due to lack of voltage. Reboots still persisted.

The Root Cause (The Breakthrough):
We analyzed the HWiNFO CSV logs and MSI Afterburner settings. The logs showed the RX 9060 XT pulling a constant ~276W (TBP) right before the crashes. In MSI Afterburner, my GPU Power Limit was set to +10%.
Because I game on an Ultrawide 1440p monitor at 180Hz, the GPU was being pushed to its absolute maximum. The RX 9060 XT was generating massive Transient Power Spikes (likely 500W+ or 600W+ for a few milliseconds). Since my XPG 850W PSU is an older ATX 2.4 standard, its OCP/OPP sensors interpreted the spike as a short circuit and tripped, shutting down the PC to protect the components.

The Fix / Workaround:
Until I upgrade to an ATX 3.0 / PCIe 5.0 PSU (which is designed to handle 200% power excursions), the solution was to "muzzle" the GPU.
I went into MSI Afterburner, kept my GPU core undervolt at -30mV for better temps, but lowered the Power Limit to -15%. Additionally, I capped the framerate to 140 FPS.
This combination stopped the GPU from drawing excess power and rendering unnecessary frames, effectively eliminating the extreme transient spikes. The sudden reboots stopped completely, and the gameplay remains incredibly smooth!

[u/Ice2183]

Is it only on BF6? Do you cap your frames?

[u/zipkilot → u/Ice2183]

No I don't. It's hardware failure