OptiPlex 980 16GB RAM Issue

Just so you don't feel all alone, I too have just discovered this issue.  I consider myself pretty technically savvy, but it took me a couple of days to get my head around what was even happening here.  Especially since the the system happily recognizes all 16GB of RAM from the BIOS and diagnostic perspectives.  My only guess at this point is that it has something to do with what model of CPU is installed in the system.  You mention "other OptiPlex 980 models" that function correctly with the 4GB DIMMS, so perhaps you could check/test that theory?  I unfortunately do not have access to any 980s with i7 processors, or I would experiment further myself.  Just a thought...good luck, and I will post more if I get any sort of answer.

Yes, I agree with J-Sellick. It might be the processor check if you have the same processors in other 980 models. If you have it then test the 4GB modules in that system else install a different processor in the non-working system and test the 4GB modules.

Sometimes the rank might be an issue too but it's highly unlikely considering other systems recognizing the same 4GB modules.

Looking forward to your post.

I also have the same problems, too.

I have the same problems too. Just bought 2 x 4GB RAM to replace the existing 2 X 2GB chips. I have tried every possible combination but PC failed to boot successfully.

I'm thinking of returning the PC as I really wanted to run 8GB of RAM.

Actually spoke with Dell regarding the 980 Small Form Factor and I don't think the PC would go higher than 4GB RAM.

Any help.

There are no ram ISSUES other than non compatible Ram.

YOU CANNOT USE 8 GIG Modules.  Absolute MAX RAM is 16 gig using 4 X  4 gig Modules.

There are Several Generations of Core I3 I5 I7 processor that ONLY SUPPORT 8 Gigs total.

The Memory Controller hub as well as the GPU are inside the CPU housing so this cannot be changed.

This is also why INTEL says

Max Memory Size (dependent on memory type)

which can be

8Gig or 16 gig or 24 gig or 32 gig max Based on the CPU.

DDR3 PC3-12800 • 9-9-9-24 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V •  512 Meg x 64 •

Thank you for updating this info.  If my reply about trying G.Skill is allowed to be posted just ignore it.  It was 1600 but not 1.35v low density I don't think.

I am going to assume you are aware my CPU is the first gen i5 650, not a later version of the Optiplex 980.

I started a new thread this weekend in desktop computers and I too have an older 980 with the i5 650 Intel chip.  I tried 4 x 4 GB of 1600 speed ram and 4 x 4 GB of 1333 and in neither case would the machine reach the desktop, though when you get to the BIOS it shows the RAM and 1333 speed.  The machine works fine with 4 x 2 GB 1333 memory, though.

I did see on the Intel site that the ram recommended includes the slower 1066, so I wonder if that would work at 4 x 4 GB in these machines.  I am twice bitten shy to order any more memory at this point.

DDR3 1066 = (PC3 8500)  too slow

DDR3 1333 (PC3 10600)  too slow

DDR3 1600 (PC3 12800)  This is the REQUIRED Speed for loading 16 Gigs of ram and it must be LOW Density.

DDR3 PC3-12800 • 9-9-9-24 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V •  512 Meg x 64 •

Many INTEL Chipsets cannot use 4 rank or 8 rank memory.

They must be low density 1R /2R or they don't work period end.

The term “rank” was created and defined by JEDEC, the memory industry standards group. On a DDR, DDR2, or DDR3 memory module, each rank has a 64-bit wide data bus.  In its simplest form, a DIMM with DRAM chips on just one side would contain a single 64-bit chunk of
 data and would be called a single- rank (1R) module.  DIMMs with chips on both sides often contain at  least two 64-bit chunks of data and are referred to as dual-rank (2R) modules.  Some DIMMs can have DRAM chips on both sides but are configured so that they contain two 64-bit data chunks on each side—four in total—and are referred to as quad-rank (4R) modules.

But I already tried this G.Skill memory from Newegg.

www.newegg.com/.../Product.aspx

1.5v is not 1.35v however I think that its HIGH Density and thats why its not working.

So, now I'm confused again.  Are you now taking back that there is actually a specific ram that will work in an i5 650 populated with 4 x 4 gig sticks of ram?

The post with the highlighted description sounded definitive, but it called for low density and 1.35v.  If I read you right now the 1.5v is correct, not the 1.35v, but since that is high density it won't work.

The bottom line now reads like:  you can't do this.:emotion-2:

Just as a reminder the machine is running 4 x 2 gigs of DDR3 1333 with no issues.

hi sir.. im using dell optiplex 980 sff. core i5 also. can I use 2 8g of ram to attain the 16g? or i have 2 existing 2g which is a total of 4g. is it possible to buy 2pcs of 4g ram to make it 12?

To be honest, I can't really remember too much about this issue, but I was never able to get my machine to run 16 gigs of ram.  I still have the machine and I settled for 8 gigs, which works fine for me.  The 16 gigs was just something to shoot for.  In my case, it was a shoot and a miss.  My feeling is that you will not be able to run 16 gigs.  Good luck.