e. remove

I assume you are thinking about leaving the RAM you have installed now in place and adding an 8GB RAM module. That is a lot of different types of RAM. It is always recommended to add RAM in pairs or 4 at a time in matched kits. That way you have the most compatible RAM installed. Crucial RAM is one of the most Dell compatible RAM types. The Hynix RAM is good RAM, I just would not recommend mixing 2 x 2 and 1 x 4 and 1 x 8.

The Crucial RAM page for your system is here.

1.5v ram is not supported.

1.35v ram is required.

Specs: DDR3 PC3-12800 • CL=11 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 1024Meg x 64 •

https://www.crucial.com/usa/en/optiplex-9020-(mini-tower)/CT4506041

It can´t be true , because as you saw , all of my RAMs are 1.5V.

It even came with 1.5V Ram when I bought it.

Even there says 1.5V : https://ark.intel.com/content/www/us/en/ark/products/75043/intel-core-i5-4570-processor-6m-cache-up-to-3-60-ghz.html

"HMT41GU6MFR8C-PB" is not listed as compatible nor is it listed as DUAL Voltage.

https://www.crucial.com/usa/en/what-is-dual-voltage-memory

LOW DENSITY ram is required.

The ram that works is VERY specific.

Kingston Value Ram and Random Hynix models are not likely to work.

MUST NOT BE HIGH DENSITY RAM.

https://www.dell.com/en-us/shop/dell-memory-upgrade-8gb-2rx8-ddr3-udimm-1600mhz/apd/a6994446/memory

Specs: DDR3 PC3-12800 • CL=11 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 1024Meg x 64 •

So if I will remove my RAM and place 2 of these 8 GB which I mentioned , will it work?

I understand , but the 8GB "HMT41GU6MFR8C-PB" has same Voltage as the others RAM which I have and they are working.

Even the https://www.dell.com/en-us/shop/dell-memory-upgrade-8gb-2rx8-ddr3-udimm-1600mhz/apd/a6994446/memory which you sent me has 1.5 Voltage

1.35v - 1.5v Dual-Voltage DDR3 Memory works.

The spec for that ram is 1.5v only

It may work but its not listed as working.

Mixing Ranks and CAS and vendors is not supported.

High Density ram is not supported.

The working ram is VERY specfic.

Sounds like almost nothing will work

@speedstep 

I'll ask again. How does one know if memory is "high density"? It doesn't seem to be mentioned in any memory specs or online listing. All I ever see are tags like 2rX8 etc.

You often talk about high density ram, and I've asked you this before, but I guess you missed it. Sure would be nice to know how to identify it.

Can you at least give some examples?

The original question is does the ram work.

The answer is it might not.

Ram Density and other parameters are not dell issues.

 High or low density?

You should always purchase only memory your system supports. In this case,only low density is compatible with your system.

@speedstep 

Again, the question is this ... If I look at a manufacturer's data sheet for a particular memory module, Exactly what parameter(s) shows this high or low "density" value?

I thought it was actually a very simple question.

Do you know the answer?

Exactly what parameter(s) shows this high or low "density value?

Density has to do with Physical construction of the modules.

All above listed are specified by JEDEC  with X4/X8/X16 data interfaces

https://www.micron.com/products/dram/ddr3-sdram

 16 GB using ONLY two memory modules must support 4 Gbit memory chips  called high density.  AMD does not care. INTEL does.

Its not simple or a standard across vendors.

Generally speaking, low-density modules are made with 16 chips, 8 on each side, using 64Mx8 device, while high-density modules are made with 16 chips, 8 chips on each side, using 128Mx4 .  Visually they look the same.

https://www.amazon.com/Crucial-PC3L-12800-Unbuffered-Density-CT2K51264BD160BJ/dp/B00A6GBN5Y/

@speedstep  Thanks!

"Its not simple or a standard across vendors."

So, if I understand, this means one can NEVER know what the density is unless it's micron brand memory.  We're just taking a shot in the dark with any other brand. Am I correct?

I believe the highly recommended crucial is actually a micron product, so it would be the only alternative.

Density has nothing whatsoever to do with being Micron or not.

Micron sells HIGH Density and LOW Density parts.

So does crucial and other vendors.

LOW DENSITY RAM is REQUIRED for DELL with INTEL CHIPSETS.

AMD Chipsets and CPU's do not care.

This crucial ram is HIGH Density

https://www.amazon.com/Crucial-PC3L-12800-Unbuffered-Density-CT2K51264BD160BJ/dp/B00A6GBN5Y/

there is also LOW Density listed on the same site.

not true  at all, you need to read the DDR data sheets to learn this is wrong

years AGO they made them all dual voltage.  ages.

so long ago the words 1.3/1.5v DDR on the sales pages, (marketing lazy sure.)

READ the data sheets, mr, speedstep. no. ( you did not)

also the data sheets on the actual DRAM show same thing done AGES AGO.

yes matched sets.

do not do this: mix size, nor mix RANK , DRAM chip counts and side counts, nor density.

The intel data sheet even warns not to mix SKU .

what is best is buying CERTIFIED for YOUR  PC DDR.  yes CORSAIR is best, they have the largest choices.

It is always warranteed.

here I will quote my one page (hard proof)

DDR3 VOLTAGE: (if you read the actual DRAM spec. the chip actual not the card they tell you flat out in the data sheet it's backwards compatible to 1.5v DDR.)   The actual datasheet DDR3 repeats it like 10 times.

• Hynix: "Hynix DDR3L   provides backward compatibility with the 1.5V DDR3"

• Crucial refers to this as Dual Voltage: In the past, most DDR3 memory voltage ranged from 1.5 - 1.65v. More recently, dual 1.35/1.5 voltage modules came available at Crucial.com. The dual-voltage module will run only run at 1.35V if your specific system (motherboard and chipset) supports that voltage, otherwise the memory will run at 1.5V.

• Kingston: As DRAM manufacturers shrink their dies and/or increase their yields of DDR3L, they soon reach a point where the majority of their DRAM output becomes DDR3L or dual-voltage, handling 1.5V or 1.35V voltages.

THEIR WORDS NOT MINE, so end this VOLTAGE WAR now.