Recently, VIA releases new BIOS for EPIA-M900 with a new function: "PMON".
By manual, when PMON is enabled, Nano x2 can run at highest 1.73 GHz.
Therefore, I test M900 with PMON enabled and compare with previous BIOS(fixed 1.6 GHz).
The results is as following:

TestResult.JPG      
You may notice that several scores have no obvious difference.
This is very curious, because these scores should be better due to increased speed.

I remember Nano's frequency control is related to temperature.
So I enhance cooling system and re-test these items.
The result is as following:
TestWithMoreCooling.JPG    
It looks more reasonable.




In order to find out the relationship between PMON and temperature, I turn fan speed to control temperature.Run two sp2004 to burn CPU, and use HWiNFO32 v3.82 to monitor temperature reading and running frequency. Then, I do find the rule about PMON:

UnderFirstThreshold.JPG      
When temperature is under 48°C, both cores run at 1.73 GHz.

OverFirstThreshold.JPG      
48°C is the first threshold. Over 48°C, one core runs at 1.73 GHz and the other runs at 1.6GHz.

UnderSecondThreshold.JPG      

OverSecondThreshold.JPG    
52°C is the second threshold. Over 52°C, both cores run at default 1.6 GHhz.




Summary:

When PMON is enabled on EPIA-M900, NANOx2 runs as following:
1. Under 48°C: Both cores run at 1.73 GHz.
2. Between 48°C ~ 52°C: One core runs at 1.73 GHz and the other runs at 1.6GHz.
3. Over 52°C: Both cores run at default 1.6 GHhz.

 

 

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