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One of the key issues with testing Raptor Lake CPUs—which many people don't fully understand (as you’ve discovered)—is the effect of Vmin Shift instability due to degradation of the clock tree circuit within each IA core. Once this degradation sets in, the CPU becomes extremely sensitive to temperature changes. This means that if the system is cool enough and the voltage is low enough, instability might not manifest immediately. However, during extended benchmarking, shader compilation, or similarly intensive workloads, the instability will eventually appear—especially under the specific types of workloads you've mentioned.
Over time, as degradation progresses, more workloads will be affected. It's just that certain tasks place more stress on the CPU, making the underlying instability easier to detect.
These effects can be scientifically demonstrated by adjusting ambient temperature—such as lowering the room temperature, removing the PC case side panel, or running the system on an open test bench. This allows for better control over thermals and helps isolate the issue.
It’s important not to evaluate this issue through the lens of temperature alone. For example, a brand-new, non-degraded CPU might hypothetically --DO NOT TRY THIS!!-- be pushed to 115°C and still remain stable (albeit thermal throttling) without triggering instability. However, as degradation sets in—particularly in Raptor Lake CPUs—the margin for thermal stability narrows significantly.
While overclocked CPUs from other generations (and non-degraded Raptor Lake chips) are also sensitive to temperature, the Vmin Shift phenomenon is unique to the 13th and 14th generation Intel processors. A degraded Raptor Lake CPU becomes increasingly unstable even within its official thermal envelope (up to 100°C). The exact temperature at which instability manifests depends on the degree of degradation or entropy the CPU has undergone—likely due to electromigration, though that would require an electron microscope to confirm. We're talking about atomic-level changes—unseen and often misunderstood, myself included—and diving into the physics behind this would be a rabbit hole for another day.
In practical terms, none of this changes the reality: you either need to tweak settings in the BIOS or Intel XTU, or pursue an RMA if the CPU is still under warranty. A quick and simplified diagnostic method—if the degradation isn’t severe—is to disable Turbo Boost in the BIOS. If doing so causes applications to suddenly become stable at the base frequency, then that’s a strong indicator your processor has been affected. Of course, all other potential hardware issues should be ruled out as well, even if the CPU remains the most likely culprit.
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Nice one PC1997 - very interesting !!
Would you say from your experience/research that mobile chips such as HX like 13950hx or 14900hx CPUs are also effected by this in any way ?
Intel have stated a few times that mobile chips are not effected even the HX range, but just wondered what you thought on that standpoint if possible ?
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Disclaimer: These statements have neither been approved nor disapproved by Intel. They reflect my own efforts to research the subject, combined with AI assistance, and have been heavily edited to correct inaccuracies to the best of my ability.
Hello IainFraser,
I’ve put together this comprehensive guide for you using AI agents to help save time. I hope it answers your questions.
Investigating Performance Degradation in Intel’s 13th and 14th Generation Mobile HX-Series CPUs: Beyond Vmin Shift
Abstract
Intel's 13th and 14th generation Core HX-series mobile processors, particularly the Core i9-13950HX and i9-14900HX, have shown instances of performance degradation over relatively short usage periods. While Intel has acknowledged a Vmin Shift issue affecting their desktop Raptor Lake CPUs, the company maintains that mobile HX-series chips are not susceptible to this specific failure mode. However, anecdotal and empirical evidence from users suggests some level of degradation still occurs. This paper explores alternative mechanisms that could contribute to early performance loss or instability in these high-end mobile CPUs, integrating both accessible explanations and technical depth.
1. Introduction
The Intel Core HX series for mobile platforms brings desktop-class performance to laptops, targeting enthusiasts, gamers, and mobile workstations. These chips—based on the same silicon as their desktop counterparts—feature high core counts (up to 24 cores), elevated TDPs, and aggressive power boosting techniques. While Intel has denied Vmin Shift issues in these mobile parts, signs of instability or degradation—such as higher voltages needed for stability, BSODs, or lowered benchmark scores—have been observed.
Given these reports, this paper seeks to:
• Define possible causes of degradation unrelated to Vmin Shift.
• Differentiate between transient software/power issues and genuine hardware-level degradation.
• Provide plausible explanations based on silicon physics, power delivery, and thermal management.
2. Background: What Is Vmin Shift?
Vmin Shift refers to the progressive increase in the minimum voltage required for a CPU to operate at a given frequency, caused primarily by:
• Electromigration: The gradual displacement of atoms in interconnects due to high current densities.
• Bias Temperature Instability (BTI): Degradation of transistor threshold voltages over time due to prolonged high voltages and temperatures.
In desktop CPUs, this manifests as instability at stock settings or a need for higher voltages to maintain advertised boost frequencies. Intel attributes the issue to aggressive tuning and workloads sustaining high frequencies/voltages, like AVX-512 or heavy multithreaded rendering.
3. Key Differences Between HX-Series Mobile CPUs and Desktop Counterparts
Intel's HX-series chips are essentially desktop dies repackaged for mobile use. However, several architectural and platform-level differences could explain why they behave differently:
Desktop (e.g., 13900K) TDP 125W (PL1), 253W (PL2)
Management: Motherboard VRMs + BIOS tuning
Mobile HX (e.g., 13950HX) 55W base, 150-157W peak power
Management: Laptop firmware-controlled with stricter thermal envelopes
These differences imply that HX CPUs are less likely to experience Vmin Shift at the same rate. However, mobile-specific stressors exist, which may lead to other forms of degradation.
4. Alternative Degradation Mechanisms
Assuming Vmin Shift is not responsible, we must consider other plausible causes of performance degradation:
4.1. Thermal Cycling and Mechanical Stress
Laptops undergo frequent temperature changes—from idle (~40°C) to load (~100°C) and back—causing repeated thermal expansion and contraction. This can lead to:
• Solder joint fatigue (especially under the die or in ball grid arrays)
• Die warping or microfractures
• Pad cratering on the PCB over time, this physical stress can degrade signal integrity or power delivery, causing instability at previously stable settings.
4.2. Aggressive Turbo Boost and PL Violations
Intel's Dynamic Tuning Technology (DTT) allows for aggressive frequency scaling based on power, thermal, and current limits. In thin-and-light laptops with high-performance profiles, CPUs frequently hit:
• Thermal limits (TJMax ~100°C)
• Short-duration power bursts (up to 157W) these high transients, especially if mismanaged by OEM firmware, can stress VRMs and lead to:
• VRM degradation, resulting in voltage droop
• Capacitor aging, reducing stability under load
4.3. Substrate and Interposer Aging
The HX-series chips are large, monolithic dies placed on complex substrates that route power and signals. Under repeated high-power states and thermal stress, substrate delamination or interposer degradation could occur—reducing power delivery efficiency and signal fidelity.
4.4. Firmware and BIOS-Induced Instability
Mobile systems depend heavily on tightly integrated firmware for power and thermal regulation. OEM BIOS updates that adjust:
• Power delivery settings
• Voltage-frequency curves
• Thermal throttling limits can mask degradation—or contribute to it. A firmware bug or overly aggressive tuning can mimic hardware instability.
4.5. Incomplete OS Power Management
Windows' power management stack (e.g., Intel DPTF and power plans) often mismanages mobile CPUs, especially after updates. These include:
• Improper turbo behavior
• Inconsistent package power limits (PL1/PL2)
• AVX offset mismanagement although not physical degradation, these factors can appear as reduced performance over time.
5. Observed Symptoms and Patterns
Reports from users and system integrators note:
• Gradual increase in CPU core voltage needed to remain stable at max boost.
• BSODs or app crashes after several months of usage under heavy load.
• Reduced all-core boost performance in workloads like Blender or Cinebench.
• Unstable undervolts that were previously stable (e.g., -100mV becomes unstable).
Most affected systems are high-performance laptops with limited cooling headroom.
6. Diagnostic Methods
To distinguish degradation from misconfiguration or software issues:
6.1. Longitudinal Monitoring
Track performance (e.g., Cinebench scores) and voltage/frequency data over time under consistent workloads and ambient conditions.
6.2. Thermal Imaging
Use IR thermography to identify VRM hotspots or uneven heat distribution suggesting hardware wear.
6.3. Firmware Rollbacks
Compare system behavior across BIOS versions to isolate software-induced regressions.
6.4. Margin Testing
Use stress tests (e.g., OCCT, Prime95) with varying voltages to detect narrowing stability margins over time.
7. Mitigation and Best Practices
• Custom fan curves: Maintain lower temperatures, especially under burst workloads.
• Undervolting with care: Avoid aggressive undervolts unless verified stable under worst-case workloads.
• BIOS updates: Apply OEM updates only after reviewing changelogs and community reports.
• Monitoring software: Use tools like HWiNFO64, Intel XTU, or ThrottleStop to monitor temps and voltages consistently.
8. Conclusion
While Intel's HX-series mobile CPUs may be protected from Vmin Shift due to lower average voltages and thermally constrained environments, they are not immune to other degradation mechanisms. The convergence of aggressive power management, tight thermal envelopes, and firmware complexity can cause real-world performance drops that resemble Vmin Shift symptoms.
Understanding these nuances is essential for OEMs, power users, and enterprise users to design better cooling solutions, firmware policies, and long-term reliability strategies. Further research with empirical silicon analysis would be necessary to quantify the root causes definitively.
References
• Intel Technical Advisory: Vmin Shift Behavior on Raptor Lake CPUs (2024)
• AnandTech Forums – Intel Mobile CPU Stability Reports
• Intel Software Developer’s Manual Vol. 3: Thermal and Power Management
• IEEE: “Failure Mechanisms in Modern Mobile Processors” (2023)
• Notebookcheck Thermal Testing Benchmarks
• Puget Systems Performance Stability Whitepapers
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the standard stress tests (e.g., OCCT, Cinebench) are not designed to reveal the specific edge-case behaviors now publicly acknowledged by Intel. These include degradation patterns under very specific workloads, many of which you’ve already listed.
To access the warranty visit this site https://supporttickets.intel.com/s/?language=en_US
While it's unlikely given your system stability prior to the BIOS update, double-check the RAM configuration against the official QVL for the ASRock B760M Steel Legend. Some BIOS updates may change RAM training behavior subtly
An access violation means that a program tried to write to an area of memory that is forbidden/inaccessible to it.
You're absolutely right @PC1997 At the end of the day, it comes down to two paths: fine-tuning the system (via BIOS or Intel XTU) or initiating an RMA process if the CPU is still within warranty. Disabling Turbo Boost is indeed a practical and telling diagnostic step if stability returns at base clock, it's a strong indicator that the CPU may be affected by the now-documented degradation issues tied to high-frequency, high-voltage boost scenarios.
Of course, as you pointed out, it’s still critical to rule out other potential hardware factors RAM, motherboard behavior, power delivery, etc. but if those check out, then the CPU remains the most probable culprit.
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