Advice needed on mixing and matching PC-8500 and PC-10600 ECC RAM, as well as requesting input on an upgrade path

[ThatTallGuy21]

Hey gang -- I have a Lenovo Thinkstation D20 with 48GB (6x8GB) of Hynix ECC RAM (purchased separately via eBay) that has been running well the past year. The stock motherboard is running two XEON processors, with the RAM occupying only 6 DIMM slots out of 12 total (i.e. 3 per CPU). 

 

I was just looking in the system profiler section of unRaid, and noticed that one of my sticks of RAM is actually different from the others. I'm not familiar with RAM terminology and could use your help making sense of some of the numbers and how to proceed. 

 

5 out of 6 sticks are the below (PC-8500):

https://www.memory4less.com/hynix-8gb-ddr3-pc8500-hmt31gr7afr4c-g7

 

1 out of 6 sticks are the below (PC-10600):

https://www.memory4less.com/hynix-8gb-ddr3-pc10600-hmt31gr7bfr4c-h9

 

• Is this ok that they're different?
  • From what I gather, which is what I'm looking to have validated, is that it's fine because the voltage is the same (1.5) so the PC-10600 stick would just run slower to the speed of the PC-8500 sticks. Is that correct?
• Also, it looks like the CAS is different between the two, but a website I saw, said that shouldn't really matter in this case, as there's no discernable difference between the two. Would you agree?
• ADDITIONALLY -- Once I figure the above out, the overall goal is to add 48GB of additional RAM. Since I've never worked with server hardware before, is there a particular direction I should proceed when adding more to my current build?
  • I.e. should I focus on sticking with Rank 2 instead of adding Quad Rank ECC Ram?
  • Should I stick with PC-8500 overall or can I mix and match under each CPU?
    • Using what I have now, should I move all the PC-8500 under one processor and use only PC-10600 under the other CPU?
  • Just looking for general advice on how people would recommend proceeding. The above is all I could think of..

 

Thanks!

[ThatTallGuy21]

Bump.

 

Does anyone have any advice? 

[JorgeB]

10 hours ago, ThatTallGuy21 said:

Is this ok that they're different?

Not ideal but usually OK, it will run at the lowest speed of the two (assuming the CPU could run the higher speed), same for CAS but in this case at the higher of the two, note that the reported CAS is for PC-10600, it will likely be the same at PC-8500.

 

10 hours ago, ThatTallGuy21 said:

I.e. should I focus on sticking with Rank 2 instead of adding Quad Rank ECC Ram?

Depending on the server more ranks can run slower, especially with 2DPC, so use minimum number of ranks available for the DIMM size you want.

 

10 hours ago, ThatTallGuy21 said:

Should I stick with PC-8500 overall or can I mix and match under each CPU?

This, like mentioned ideally all DIMMs should be identical.