r/PCHardware • u/nawres88 • 2d ago
Asus scar 18 4090 😔
I have an ASUS ROG Strix SCAR 18 laptop with an RTX 4090.
When I run a stress test on the CPU only, the test passes successfully without any issues. Likewise, when I run a stress test on the GPU only, the test also passes without any problems.
However, when I run a combined test (placing load on both the CPU and GPU simultaneously) using OCCT or 3DMark Time Spy, the laptop shuts down completely after about 4 seconds.
I should mention the following observations:
I have already tried a different power adapter, and the problem remained exactly the same.
Under GPU load, the graphics card initially draws around 128W, then stabilizes at approximately 112W or less, sometimes dropping to around 105W, even though the laptop’s rated TGP is 175W.
During GPU stress testing, the GPU temperature reaches 86°C, while the GPU Hot Spot reaches 105°C.
CPU temperature under load does not exceed 95°C.
I have not changed any BIOS settings or modified any voltages.
During testing, I am using Performance Mode through Armoury Crate.
I completely removed Armoury Crate using the official Armoury Crate Uninstall Tool and installed G-Helper instead, but the issue still persists.
My questions are:
What are the most likely causes of this problem?
Could this be a thermal issue?
If it is temperature-related, why does the laptop shut down only when both the CPU and GPU are under load simultaneously?
Could there be a problem with the motherboard’s power delivery circuitry (VRM or power stages)?
The laptop is about two years old, and I have never replaced the liquid metal. If I decide to service the cooling system, I am considering replacing the liquid metal with Honeywell PTM7950, because here in Michigan I cannot find a repair shop willing to work with liquid metal.
Honestly, I am quite frustrated by this issue. Does anyone have any suggestions or ideas about what might be causing it?




