Question CPU behaviour in gaming versus stress test ?

[naczelnik5]

I wonder about the behavior of my Ryzen 7800X3D CPU. I have the PBO curve set to -20 and PPT to 80W. In CR23 the temperatures do not exceed 78C and reach 18500 points. Playing The Last of Us Part II where shaders are loaded on the fly, I noticed usage and temperature jumps which is logical.
I am just curious why during the synthetic stress test where the CPU usage is at 100% the temperature is max 78C. But while playing The Last of Us Part II there are momentary usage jumps to e.g. 90% and the temperature momentarily jumps to 84C ?

 

[rgd1101]

depend on what the test and game is using. a cpu can do all kind of thing.

 

[naczelnik5]

depend on what the test and game is using. a cpu can do all kind of thing.

You're probably right. I looked through the CPU monitoring in the form of a graph. The spikes in usage and temperature are very short while gaming, which is why I conclude that the CPU cooling won't have time to react. This could also be the cause. What's the deal with the max temp when it comes to the 7800x3d? It's written almost everywhere that it's 89C for this cpu. However, in official AMD articles regarding the 7000 processors, they claim that the max temp for the entire series is 95C?

 

[geofelt]

Stress tests and such benchmarks use instructions and patterns that will be very different from what your game used. Some are designed to generate heat to exercise your cooling. Intel burn test, for example.

Processors monitor their temperatures(of which there are many).
If a dangerous point is reached, the processor will slow down or even shut off to protect itself.
89C may be one of them.

Occasional temporary throttling is not a problem.
Constant throttling is a problem.
Look at deliberate overclocking or a poorly functioning cooling system.

 

[kgt1182]

The CPU stress test only stresses the CPU cores hard.
A CPU is more than its cores, it contains Memory controllers and yes, cache which the Ryzen 7800X3D has a lot of as stacked 3D cache.

When gaming, the games use the 3D cache for faster shader loading to reduce RAM waits to improve performance.
This means that more heat may be produced across the entire chip at times when cores and cache are used at 90% compared to only the cores at 100%.

In semiconductors, 3D cache tends to have temperature spikes. This is because the cache are stacked on top of each other, and hence heat may momentarily collect under the cache when it is used to load data.

 

[naczelnik5]

The CPU stress test only stresses the CPU cores hard.
A CPU is more than its cores, it contains Memory controllers and yes, cache which the Ryzen 7800X3D has a lot of as stacked 3D cache.

When gaming, the games use the 3D cache for faster shader loading to reduce RAM waits to improve performance.
This means that more heat may be produced across the entire chip at times when cores and cache are used at 90% compared to only the cores at 100%.

In semiconductors, 3D cache tends to have temperature spikes. This is because the cache are stacked on top of each other, and hence heat may momentarily collect under the cache when it is used to load data.

Thanks for the explanation. I didn't take into account the 3D v-cache which is not used in synthetic tests. Now it makes sense