Optiplex 7040SFF DIMM1 and DIMM3 memory failure

Question

Testing with known good RAM from DIMM2 and DIMM4 (M378A1G43DB0 CPB and M378A1K43BB1 CPB) in DIMM1 and DIMM3 results in 2 amber short pause and 7 amber then repeats 2/7 etc... From Dell's 7040 PDF this appears to be memory failure. Tested all sticks (above models and two MSL4U213FF8GX2) with DIMM2 and I don't get any failures. Also tried to reseat the CPU same issue.

What could be wrong with DIMM1 and DIMM3 such that it always fails?

Dell Optiplex 7040SFF, BIOS 1.22.0, 4304.16 UEFI ROM.

bradthetechnut · Accepted Answer

Replacing the 7040 is a good idea.  If DIMMS die, there isn't a way to fix that other than replace the MB or take it to a computer shop and see if it's some capacitor.

dereks · Answer

Sorry 7040SFF

bradthetechnut · Answer

Dirt Bent pins Faulty MB MB's are quite reasonable on eBay.  Remember to include form factor/size in your search term (MT, SFF, etc.).

bradthetechnut · Answer

That's ok, no worry.  I see it's in your subject line now.

dereks · Answer

I'm not sure if this is telling of anything however looking at the BIOS and Intel ME hardware info DIMM2 and DIMM4 are in single channel mode. That's with any combination of memory from the first post.

However, pulling two sticks from a Dell 3080 Tower (HMA81GU6CJR8N-XN 8G DDR4 3200 and TD48G26S819-VC 8G DDR4 2666) where they are running in dual channel mode on the 3080 they also appear as single channel on the Optiplex 7040SFF.

Does this have any meaningful info on why DIMM1 and DIMM3 are not working? It seem I can't get DIMM2 and DIMM4 in dual channel.

Also, testing the 3080's memory in DIMM1 and DIMM3 results in the same 2/7 led error at boot.

dereks · Answer

I've been given the option to replace the 7040SFF buy the seller with the assumption this is a motherboard issue.  Any other recommendations before I start the process and ship this back to the seller?   Everything from above appears to checkout?  All the RAM should be compatible with the 7040SFF?

bradthetechnut · Answer

I'm not 100% sure if you mixed the RAM or not. If speeds are mixed, and all the RAM works, it'll work at the speed of the slowest stick. Doesn't mean it never works, but mixing RAM in Dell's isn't recommended. Sometimes Dell's can get finicky and throw an error code if just the brands are mixed. It especially won't work if voltages are mixed.

I was hoping another might chime in as I'm mostly unable to answer questions about dual and single channel.

dereks · Answer

I'm less concerned about dual/single channel and more concerned about DIMM1 and DIMM3 causing a 2/7 led error when working memory is in those slots.

dereks · Answer

Replacing the machine (in turn the board) and everything is working as expected.  All RAM slots are populated and are in dual channel mode.

bradthetechnut · Answer

Glad you got it working.  : )

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Optiplex 7040SFF DIMM1 and DIMM3 memory failure

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