View source for Minisforum MS-A2 9955HX temperature fix

= CPU Thermal Performance Analysis =

== What I Found ==

'''Bottom Line:''' Through systematic testing, I discovered that the AMD 9955HX's default thermal settings prioritize maximum performance at the cost of longevity. By adjusting the TJmax setting from 96°C to 78°C in the UEFI, the system runs 15 degrees cooler with only a 5% performance reduction while extending CPU lifespan by approximately 800%. This simple UEFI modification addresses a significant thermal management shortcoming in an otherwise excellent high-performance system.

* '''Performance Loss:''' Only 5% reduction from default settings
* '''Temperature Drop:''' Runs 15°C cooler (from 95°C to 81°C)
* '''Lifespan Extension:''' From ~1 year to ~8 years under continuous operation

=== What is TJmax? ===
TJmax is the maximum temperature setting in the BIOS that tells the CPU when to start slowing down to avoid overheating - by lowering this from the default of 96°C to 78°C, we're essentially telling the CPU to be more conservative about heat.

== CPU Lifespan vs Operating Temperature ==

Based on electromigration studies and the Arrhenius equation, higher temperatures dramatically reduce CPU lifespan. The following shows expected lifespan for continuous 24/7 operation:

[[Image:Cpu-lifespan-vs-temperature2.png|thumb|right|CPU Lifespan by temperature]]

{| class="wikitable"
|-
! Temperature (°C) !! Expected Lifespan (Years)
|-
| 50°C || ~50 years
|-
| 60°C || ~30 years
|-
| 70°C || ~18 years
|-
| 80°C || ~8 years
|-
| 90°C || ~4 years
|-
| 100°C || ~1.5 years
|-
| 110°C || ~0.5 years
|}

== Performance vs Temperature Analysis ==

Comparison of four different CPUs showing the relationship between thermal management and performance. The '''78°C anomaly''' on the 9955HX shows improved performance with lower temperature.


[[Image:File:Various-cpu-efficiency-heat.png|thumb|right|Various cpu performance by temperature chart]]


{| class="wikitable"
|-
! CPU Model !! Max Temp (°C) !! Passmark Score !! Performance Class
|-
| AMD 9955HX (Optimized) || 81.1 || 56,711 || High-End Mobile
|-
| Intel i9-13900K || 80 || 57,005 || High-End Desktop
|-
| (Minisforums) AMD AI370 || 95 || 33,036 || AI-Focused (Throttled)
|-
| Intel N150 || 71 || 6,076 || Ultra Low Power
|}

== AMD 9955HX Detailed Results ==

=== TJmax Settings (Primary Focus) ===


[[Image:File:Minisforums-ms-a2-temperature-78c-tjmax.png|thumb|right|Minisforums ms-a2 TJmax vs performance]]


{| class="wikitable"
|-
! TJmax Setting !! Actual Temp (°C) !! Passmark Score !! Tokens/Sec (Qwen3 8B) !! Performance vs Stock !! Est. Lifespan
|-
| Stock (96°C) || 95.5 || 59,862 || 4.1 || 100% || ~1 year
|-
| 90°C || 92 || 56,947 || - || 95% || ~4 years
|-
| 85°C || 86 || 57,037 || - || 95% || ~8 years
|-
| 80°C || 81.5 || 56,130 || - || 94% || ~8 years
|-
| style="background-color: #4ecdc4; color: #000; font-weight: bold;" | '''78°C (Optimal)''' || '''81.1''' || '''56,711''' || '''4.63''' || '''95%''' || '''~8 years'''
|-
| 75°C || 76 || 44,199 || - || 74% || ~18 years
|-
| 70°C || 71 || 34,281 || - || 57% || ~30 years
|}

=== Alternative Settings Testing ===

I tested various Windows and BIOS settings to see if they could control temperature and performance, but most had minimal impact compared to the TJmax setting.

{| class="wikitable"
|-
! Setting Type !! Max Temp (°C) !! Passmark Score !! Tokens/Sec (Qwen3 8B) !! Notes
|-
| Stock BIOS || 95.5 || 59,862 || 4.1 || Default settings
|-
| Windows Efficient || 94.5 || 59,597 || - || Minimal difference
|-
| Silent Mode || 96 || 58,949 || - || Slight performance drop
|-
| 75W Power Limit || 95 || 57,344 || - || Power limited
|-
| 55W Power Limit || 95 || 56,414 || - || Severely power limited
|-
| Turbo Off || 67.4 || 32,206 || 4.6 || Major performance loss
|-
| style="background-color: #4ecdc4; color: #000; font-weight: bold;" | '''78°C TJmax (Optimal)''' || '''81.1''' || '''56,711''' || '''4.63''' || '''Best balance found'''
|}

== Reference CPU Comparison ==

{| class="wikitable"
|-
! CPU Model !! Max Temp (°C) !! Passmark Score !! Tokens/Sec (Qwen3 8B) !! Performance Class
|-
| AMD 9955HX (Optimized) || 81.1 || 56,711 || 4.63 || High-End Mobile
|-
| Intel i9-13900K || 80 || 57,005 || 6.30 || High-End Desktop
|-
| (Minisforums) AMD AI370 || 95 || 33,036 || 3.54 || AI-Focused (Throttled)
|-
| Intel N150 || 71 || 6,076 || <0.2 || Ultra Low Power
|-
| Nvidia 4090 || - || - || 79.4 || GPU Reference
|}

== Key Findings ==

=== The 78°C Anomaly ===
* Performance jump from 80°C setting
* Temperature actually decreased
* Suggests optimal thermal design point
* Better than default configuration

=== Thermal Throttling Wall ===
* Massive performance drop below 78°C
* 75°C: 26% performance loss
* 70°C: 43% performance loss
* Clear thermal design limitation

=== Efficiency vs Performance ===
* Default: Maximum performance, 1-year lifespan
* 78°C: 95% performance, 8-year lifespan
* Power profiles had minimal impact
* TJmax setting is the key control

== Final Analysis ==

=== Recommendations for AMD 9955HX ===

'''Optimal Setting:''' TJmax 78°C in BIOS provides the best balance of performance and longevity.

==== Why 78°C is Perfect: ====
* '''Performance:''' Retains 95% of maximum performance (only 5% loss)
* '''Temperature:''' Reduces operating temperature by 15°C
* '''Longevity:''' Extends CPU lifespan from ~1 year to ~8 years under continuous load
* '''Efficiency:''' Optimal thermal design point discovered through testing

==== Key Insights: ====
* '''Thermal Optimization:''' Default 96°C setting prioritizes peak performance over longevity
* '''Sweet Spot Discovery:''' The 78°C anomaly shows better performance than 80°C setting, indicating precise thermal optimization
* '''Power Profiles Ineffective:''' Windows power management and BIOS power limits had minimal impact compared to TJmax setting
* '''Thermal Wall:''' Performance drops dramatically below 78°C due to aggressive thermal throttling

==== Server/Long-term Use: ====
With 78°C TJmax setting, this CPU is now suitable for server applications with minimal performance sacrifice and dramatically extended lifespan. The temperature reduction also means lower cooling costs and reduced system stress.

== Additional Benchmark Data ==

=== Complete Test Results ===

{| class="wikitable"
|-
! Test Configuration !! Prime95 Max (°C) !! Passmark Score !! Passmark Temp (°C) !! Corecrunch Time (s) !! Corecrunch Temp (°C) !! Qwen3 8B (tokens/sec)
|-
| Stock BIOS || 95.8 || 59,862 || 95.5 || 52.9 || 83.6 || 4.1
|-
| 78°C TJmax || 82.6 || 56,711 || 81.1 || 52.9 || 79.4 || 4.63
|-
| Turbo Off || - || 32,206 || 67.4 || 117.2 || - || 4.6
|}

'''Note:''' The 78°C TJmax setting shows improved AI inference performance (4.63 vs 4.1 tokens/sec) while running significantly cooler, demonstrating that optimal thermal settings can actually improve performance in sustained workloads.

[[Category:Hardware]]
[[Category:CPU]]
[[Category:Performance Tuning]]