Thank you for sharing this information, because with the now good long life support of Intel processor you do not want other devices on the board to go end-of-life.
A remark on actually using the memory above +85°C, see your datasheet:
- Average refresh period
- 7.8 µs at 0°C ≤ Tc ≤ +85°C
- 3.9 µs at +85°C < Tc ≤ +95°C
So for this the BIOS needs to be customized to set the memory refresh period to 3.9 µs.
Good you have also implemented this feature in the SPD EEPROM on the memory module. In this case the (customized) BIOS can set the refresh period corresponding the bit in the EEPROM.
Frank van Weerdenburg
You are perfectly right.
With an SPD Eeprom having an integrated Temperature Sensor you can set the system (via SPD settings) in a way that it adjusts the refresh rate on its own depending on the actual temperature. Also you can activate ASR mode in the SPD which takes automatic care of the refresh rate in self-refresh mode.
Or alternatively you could permanently set the refresh rate to 3.9µs, which costs a bit of performance (not too much though)
The DDR3 JEDEC standard states that the refresh rate needs to be doubled when the tCase (temperature on DRAM-surface) exceeds 85°C. The same rule also applies for other memory technologies such as DDR2 or DDR4 or LPDDR4.
Reason: Operating at high temperature reduces the data-retention time of the memory-cells due to higher leakage, which can lead to random & transient single bit errors. To work against this, doubling the refresh rate is very effective.
Bit-flips in memory can also occur due to numerous other reasons (radiation, intensive operating, VRT effects), while high temperature surely is the most critical.
An addition method to make systems highly reliable / to reduce the frequence "single event upsets" is to use ECC error-correction on the memory. This requires the memory bit-width to be expanded from 64 to 72 bits to store the additional parity data for ECC, so you need more components.
Intelligent Memory also has DRAM with "on chip ECC", which means the ECC is executed by the DRAM, thus the CPU does not need to be ECC capable. But such ECC DRAMs are only available from IM in small capacity like 1 Gigabit (DDR1, DDR2, DDR3).
New DDR4 8Gb with ECC and also LPDDR4 4Gb+8Gb with integrated ECC are planned to be released by Intelligent Memory later this year or next year.
I have a question:
I see some boards with Apollo Lake having two SO-DIMM sockets.
As the 8 Gigabit DDR3L components are working well, a Dual-Rank SO-DIMM can have 16 Gigabyte.
Has anybody ever tested if the Apollo Lake can be expanded to 32GB by using 2 pieces of 16GB modules?
Unfortunately I have no board with two SO-DIMM sockets on hand. But if anybody here in the forum would like to try, we can send samples to test.
Thank for contacting Intel Embedded Community.
In order to be on the same page, could you please let us know the part numbers and SKUs related to this situation? By the way, could you tell us if the affected is a third-party design or it has been developed by you? In case that it is a third-party device, could you please give us all the information related to it?
Wating for your reply.
The Intel Oxbow Hill CRB with the Apollo Lake-I supports 2x DDR3L non-ECC SODIMMs up to 1867 MT/s.
I now just checked the user guide (565487), it mentions: up to a total of 8 GB.
Seems like Apollo Lake platform memory capacity maximum supported is 8GB.
My question to Intel is: will the new planned revision of Apollo Lake I (Long Life Stepping F-1) have support for up to 16 GB?
Frank van Weerdenburg
my question is generally related to Apollo Lake series Intel Atom E39xx.
I am interested find out what the maximum memory upgrade for the Apollo Lake will be.
We already know that the E39xx supports DDR3L components with 8Gb capacity as we have boards equipped with 8 pieces of 8Gb components working.
But some motherboards with Apollo Lake have SO-DIMM sockets. If an SO-DIMM is built with 8Gb DDR3L components, it will have the very special capacity of 16GB per each module.
We do have such modules readily in stock. We now like to try if a motherboard with two sockets - for example the AAEON COM-APLC6 or any other, will work with two modules and operate with 32GB total memory.
Maybe one of the users here in the forum have such a board with two sockets and would like to check that? I could send two 16GB SO-DIMMs to try.
Thanks for your reply.
You have mentioned the maximum capacity stated as the suggested by Intel. You can confirm this information on page 25 of the IOTG Apollo Lake Platform Design-In Presentation document # 557198.
However, if you want to use any configuration or specification out of the stated in the documentation, it should be tested and validated on your own.
By the way, the cited document is accessible when you are logged into your Resource & Design Center (RDC) privileged account. It can be requested by filling out the RDC Account Support form.
We hope that this information may help you.