SPD information not available on C422 chipset, ECC Registered

Ivo

New Member
Hi all,
Hi Martin,

I want to report that there is no SPD information ( for each module- they are "emtpy" ) on Dell T5820 Precision workstation with Intel Xeon W-2155.
Installed memory is 4 x Samsung M393A2G40DB0-CPB , 16 GB each. Otherwise temperature sensors for each module are readable with hwinfo.
This is with the latest BIOS 2.8.0.

(Also SPD information is not available under linux 5.10.12 kernel ( with ee1004 module - which can get SPD from DDR4) . Using decode-dimms and i2cdetect. )

Thanks ,

Ivo
 
This is most likely due to Closed Loop Thermal Throttling (CLTT) - a mode which when activated in BIOS causes the IMC to periodically read DIMM temperatures (TSOD) via SMBus/I2C. This blocks all others from accessing the DIMM SPD information.
 
This is most likely due to Closed Loop Thermal Throttling (CLTT) - a mode which when activated in BIOS causes the IMC to periodically read DIMM temperatures (TSOD) via SMBus/I2C. This blocks all others from accessing the DIMM SPD information.

Yes, seems to be you are right
 
Just for information regarding this model workstation : there is no option in the BIOS to disable Thermal Sensor on DIMM.
 
It depends on BIOS whether it allows changing the memory thermal management.
If such an option is available then, then it's most likely called like "Memory Thermal Management Mode", OLTT/CLTT or similar.
 
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