XPS 8940, memory upgrade of 2x8GB

Probably should mention this was the RAM I purchased  Dell Memory Upgrade - 8GB - 1Rx8 DDR4 UDIMM 3200MHz | Dell Canada

It was marked for use in XPS 8940

@Jon-62 

No, both are labeled as "Crucial 32GB Kit (2 x 16GB) DDR4-3200 UDIMM"

Yes, that's the part number for a 2 x 16MB kit.

@RaymondGarcia, try to put the same brand ram in slot 1& 2 for onde and un slot 3 & 4 for thé other

it s work for me in my xps at 2933mhz in dual Channel mode

not logical but works

@Jon-62 

Any idea what the difference between CT2K16G4DFRA32A and CT2K16G4DFD832A is?

It's the package.  You need UDIMM 288-pin package DDR4 memory.  CT2K16G4DFD832A is SODIMM 260-pin package DDR4 memory for laptops.

@Fadadas Great to hear it worked for you.  Maybe there is hope.  No I tried every combination order I can think off with 4x8GB with the RAM I have.  It always goes back to 2400 MHz.  I guess you lucked out.  DELL does not officially support 4x8GB so they don't have any solutions.  Now as mentioned in my system they gave me 2 different manufactures of RAM (Micron and SK Hynix) they have the exact same timings (as noted above) and any combination of new and old RAM Micron and SK Hynix works when I have 2x8GB.  Go to 4x8GB and it drops to 2400 MHz.  Luck of the draw I guess.  Glad you got lucky.  

@RaymondGarcia My xps i9 came with 2*8 go Sk hynix on slot 1 and 3

i bougth  2*8 crucial 3200 cl 22 1.2v to have 32 go ram

first i install thèse new ram in slot 2 and 4 => 2400 mhz

then in test with only crucial ram in place of hynix => 16 go ram at 2933mhz

After i test to put hynix in slot 1 and 2 (Black and white slot) and put crucial in slot 3 and 4 otherwhite and black slot

thats mean that i have not the same brand of memory  in white slots. neither on black slots

the dual Channel stell work in this configuration and the frequency is 2933 only in this configuration 

Thank you for your help! 

Sorry, my bad.  Just checked on Crucial UK website and the difference is subtle.  One is single ranked whilst the other is dual ranked.  Single ranked RAM is better (and faster), as it requires a single access rather than double access to get the data.  The single ranked memory is CT2K16G4DFRA32A.

Very odd that mixing pairs in each bank allows the RAM to run at 2933 MHz.

Have any of you tried the latest XPS 8940 BIOS update?

Yes i was  surprised to.

works before and after the update of the last  bios

@Fadadas  can you please post the link of the exact Crucial RAM stick you bought ? I will try to get the same and hope for the best... Thanks!

@sck90 , CT8G4DFRA32A

buy here : Crucial (8Go DDR4 3200 PC25600) - Mémoire PC Crucial sur Cybertek.fr

@Fadadas  Thanks ! This seems to be a Europe based website, but I'll try to find the same in Canada.