Mini Tower/Desktop/Small Form Factor has 4 DIMM slots while Ultra Small Form Factor only has 2 DIMM slots.
You need 64 bit to run more than 4gb RAM which I assume you already have. Depending on which version you have, you can fit 2x4gb to 4x4gb ram. It depends on how much you're willing to spend, and I'm sure I saw some sticks that hold 8gb each before too If I'm not mistaken BUT they're really costly.
Windermint, not sure why you are giving me that url. I made clear that I already found out what Dell says, and what several memory webites say, and it doesn't agree, so that's why I came here. So you give me the URL for a website that says nothing about the memory limit, so, what am I supposed to read on that site?
Emerald, thanks, same thing Crucial says. But it disagrees with Dell's specs as I've noted. I am looking for help knowing which is right and how they disagree. Any help?
Call Dell, you may think 4GB because that's what it came w/ - doesn't mean it's the max, when you look at specs from Dell that's normally the spec when it was released, which may have been a max of 8GB, they may have since released a BIOS update that allows for using 4GB sticks in which case it's 16....Off hand I myself don't know for sure, when I try and help here, I go by specs, but most of us here don't really have the time to make calls for you
Yes, Dell Optiplex 780 (Desktop, SFF, Mini-Tower) supports a max memory of 16GB. It has 4 slots and max per slot is 4GB. And Dell Optiplex 780 (U-SFF) supports a max memory of 8GB. It has 2 slots and max per slot is 4GB. Dell also confirms that it supports 16GB/8GB for your system. You can refer the Dell's Technical Guidebook(<-- Click here!!) to confirm the same.
Usually, whenever a model is launched they tend to release the spec according to the technology available at that time and most often they do not update their specification after that. Sometimes after the release they may add additional feature to your system which can be utilized if your system has the latest BIOS firmware. The memory retailers (some) and manufacturers work closely with Dell and that's the reason they get the information which is normally not available to the user.