i.MX8MQ with DDR4 RAM configuration - it goes in abnormal overheating

[MarcoSandrelli]

We've designed two modules with i.MX8M (i.MX8M link), the first with 4GB LPDDR4 (1.6GHz), the second with 4GB DDR4(1.2GHz).

For both DDR solutions, we've followed NXP ref schematic. The systems work well and are stable. The kernel used is 4.19, but we tried also with the latest 5.4 released for the evk.

The only difference we're seeing, is the thermal behavior.

The module with DDR4 design shows about 15/20°C greater than the module with LPDDR4 in the same software and load condition: the system is a login (linux filesystem) in IDLE, no CPU load, with HDMI FHD output.

The CPU hardware design guide indicates that DDR4 can’t go at low freq and it will consume more power

but 20°C in comparison with LPDDR4 seem too much.

Did you have any feedback on i.MX8M SOC with DDR4 memory for what concern thermal behavior ?

Thanks

[Rita_Wang]

The i.MX8MQ SOC can not support DLL-OFF mode.

When CPU in idle, the lowest frequency of DDR4 is 667Mhz(or Micron chip with 533Mhz), and the lowest frequency of LPDDR4 may be 25Mhz. So there be a difference on power consumption between LPDDR4 and DDR4 module.

We don't have the data comparing SOC power consumption of using LPDDR4 and DDR4 when system in idle.

I think that users will see the smaller gap of power consumption when both system is in high frequency.