Question How do i get a Dell t7400 to recognize 128GB?

Mar 5, 2019
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Dell precision T7400 Dual quad Xenon E5420. Upgraded from 32 GB to 128GB of Ram, with risers. Bios (A11) sees 16 8GB sticks but tells me 64GB installed. Windows 10 says 64 GB available, 64GB hardware reserved. MEMTEST OK. Contemporaneous Dell blurbs claim it supports 128GB. How do make the remaining ram available?
 
Are you working with the same load out of rams on each slot? To add, which version of Windows 10 are you on? You may want to see if you an remove CMOS battery and replace after 15 mins. See if that allows system to see all of your ram.
 
Hello
I have the same problem here. 16 pieces (identical) of 8gb SAMSUNG 5300F. And in bios is recognized only as 64GB
Just for the historical record, isolated the problem to a bad (apparently reproduction) riser power cable. Everything works now.
How did you come to the conclusion that this is a problem with cables? The multimeter shows 12V on all four cables in raisers. So this is the right value (I think)

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Situation was 64 out of 128GB were available, 64 GB hardware reserved. All 128 GB visible by the BIOS. I was working on something else in the case and disturbed one of the power cables. Available memory dropped to 32/128. After reseating the cables it went back to 64/128. So on a hunch I purchased a genuine Dell cable and now all 128 work. I had 12V too, but there it is. I put the defective cable into a different T7400 with 64GB, and the available RAM dropped to 32. I've convinced myself it's the cable, but I can't explain what is wrong with it.