Optiplex 780 RAM

Good day Brent ,

Thank you for writing to the Dell Community Forum .

This system is designed to support DDR3 SDRAM (non-ECC memory only ) with transfer rates varying from 800, 1066, 1333 and 1600 megahertz.

DDR3 also allows for chip capacities from 512 MB to 8 GB but the maximum limit upto which the memory capacity can be extended is 16GB .

Note :DDR memory can run in dual-channel mode, which allows the system to have twice the memory bandwidth using the same memory technology.Dual-channel mode is always present when both memory channels are populated. However, for optimum dual-channel performance, the size of the modules must match.

I hope this helps .If there are any more queries do reply to this post .

Have a good day ahead .

Kindest regards,

Wow I never saw anywhere that said this can use 1600mz DDR3. The bus is listed as 1333mhz. Does this mean if I buy 1600MHZ it will just downgrade? I want the most bang for my buck RAM.

Do I have to buy RAM that says it is dual channel, or is all DDR3 compatible?

Hi Brent ,

Thank you for the reply .

This system is designed to support DDR3 SDRAM( non ECC memory only ) .

The frequency that system support  are 1333 and 1600 megahertz  ( so that answers your question where in the system will not downgrade to a lower frequency range ) .

Kind Regards ,

I hate to poster people, but this is why I am confused:

According to the tech sheet:

http://i.dell.com/sites/doccontent/shared-content/data-sheets/en/Documents/optiplex_780_tech_spec_sheet.pdf

My system can have up to 16GB of 1333Mhz non-ecc DDR 3

According to the Tech Guide:

http://www.dell.com/downloads/global/products/optix/en/optiplex_780_tech_guidebook_en.pdf

My computer can have up to 8GB of 1066mhz  DDR3 (maybe because larger or faster capacity chips weren't available to test it with back then?). Notice how it says DDR3 at the top and DDR2 in the list of RAM types.

This guy on the support form says he got his to work with 1333mhz RAM, but it down clocked it to 1066mhz:

http://en.community.dell.com/support-forums/desktop/f/3514/t/19591189

Here is another guy with the updated BIOS who had 1333mhz work, but the BIOS shows it at 1066MHZ:

http://en.community.dell.com/support-forums/desktop/f/3514/t/19579385?pi21953=1

Here is another Tech guide that says faster RAM will clock down to 1066MHZ:

http://i.dell.com/sites/content/business/solutions/engineering-docs/en/Documents/optiplex-780-tech-guide.pdf

So you see why I am confused. I am not sure which guides are right and are with the updates BIOS.

Some people may put in 1333mhz and not see that it is running at 1066mhz. I don't see anyone who says they are getting chips to run at 1333mhz.

I just popped out a RAM chip and it is Samsung PC10600 1333mhz. I have the latest BIOS. It shows it as 1066mhz in the BIOS. This adds to my belief that 1066Mhz is the fastest for the 780MT.

Hi Brent ,

Thank you for writing to us.

I would ask you to provide the service tag of the system ( send it via private message ) so that I can check the specifications of the system to get more clarity on this .

Awaiting your response .

Kindest Regards ,