Poweredge R720 Low Memory Frequency

Question

Hi everyone!

I'm having an issue with Quad-Rank RAM-modules that should be able to go up to 1866Mhz but are clocked down to 1333Mhz.

Memory Modules:

I got 12 of them from a friend of mine, and they are specified at 1866Mhz. They are however Quad-Rank modules that are load-reduced but that shouldn't be a problem.

I have tried to just insert one, two, and of course filled A1-A4 and B1-B4 but no dice. (As per Dells recommendation for best performance).Set performance mode on the server (usually have performance per OS).

And before anyone asks, yes the CPU should support speeds of 1866Mhz:

I have been looking all over for a good answer to this topic for a while now, and can't seem to find a reliable answer to why it's not working, and if it should be working.Firmware updates always unlocks more potential in these old-servers but the documentation does not. There might even be another update I'm not aware of that I can try, but I haven't found one that's newer.

I've been checking this link for information, but it hasn't really helped me out. I'm probably just not reading it correctly.
https://www.dell.com/support/manuals/sv-se/poweredge-r720/720720xdom/system-memory?guid=guid-7550b0f0-b658-4f09-a3f8-668d9ced36ae&lang=en-us

I'm thankful for all the help I can get on this matter

MiniMaleN · Accepted Answer

I did try the one-stick-at-a-time approach with the server, and it turns out that one of the sticks were in fact, not 14900L, rather 10000-something-L.

So my friend who gave me the Modules and helped me with them didn't know this, and assured me that they were all the same.
So, long story short, one module clocked them all down.

Many thanks for your help in this matter, and I'm sorry for taking up your time!

DELL-Chris H · Answer

MiniMaleN,

As seen on page 42 of the manual you provided the link to, LRDimms are only able to run at 1866 when there is only a single dimm per channel, if you run 3 it is liited to 1333.

Let me know if this helps.

MiniMaleN · Answer

Hi Chris, When I have modules in A1, A2, A3, and A4 and then B1, B2, B3, and B4. Arent these 1 Dimm per channel? Or have i missed something?

MiniMaleN · Answer

Right now I have the memory in place like this: (Red lines are modules)

MiniMaleN · Answer

But they should still be running at 1600Mhz which is not happening either.

DELL-Chris H · Answer

Would you confirm the part number for the dimms, as well as their voltage?

DELL-Chris H · Answer

Would you confirm the Memory Mode, as well as if the BIOS and iDrac are up to date?

DELL-Chris H · Answer

Looking at the image you provided, the dimms are not a single dimm per channel, you are running 2 dimms per channel. For example A1 and B1 are both on channel 0, where A2 and B2 are on channel 1, etc.

MiniMaleN · Answer

The memory mode is Optimized and these are the versions of BIOS and Firmware:

MiniMaleN · Answer

If by part number you mean this? M386B4G70BM0-CMA4Q - 32GB 4Rx4 PC3-14900L DDR3-1866MHz And the voltage is 1.5V

MiniMaleN · Answer

Oh, so Channel 0 for B1 and channel 0 for A1 are the same channels? So I need to put one 32GB in A1 One in B2, One in A3 and One in B4 to get 1866Mhz?Or am I totally wrong here?

DELL-Chris H · Answer

Thank you.

Would you be able to run and export a TSR for me, and then upload it to https://dell.to/3fyE23S? You can find a walkthrough here on doing so. After uploading it would you then private message me the svc tag used to upload so I may retrieve it?

Thank you.

MiniMaleN · Answer

You have received a PM with what you need!

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Poweredge R720 Low Memory Frequency

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