Memory error detected. Limit exceeded. additional errors will not be resolved (Dell XPS 9350)

You've got a bad memory module or a bad memory socket.  

First thing:  Unplug the system, disconnect the battery from the mainboard and remove and gently clean (a pencil eraser is a good tool for this) the module(s).  Re-install both modules, reconnect the battery and powerup. Press f12 a few times at powerup and boot into the diagnostics.  Run the quick tests, and then select the extensive memory test.  

If you see the same error again, try one module at a time in each socket until the error disappears.  If one module fails in both sockets, replace it.  If both modules fail in the same socket, the only real fix is to replace the system board, unless you're OK with running just one memory module.

Thank you for your reply, but I have built-in memories! Do you have any idea how much the motherboard will cost? and if it is trustful to get it from anywhere online?

Do you have any idea what are the causes of this problem? i'm not sure if Dell is following a new approach in terms of a product lifetime!

I bought a new Dell XPS 9310 this week and I'm thinking to return it back, as what I see Dell is started to do everything soldered on the mainboard (RAM, and even the wireless card they did it soldered on the mainboard!)

I mis-read the 9350 as 9530 -- which would be the 15"model with separate memory modules.  You're correct -- the RAM you have is LPDDR3 and soldered on.

The cost of a board will depend on the CPU you have (or want) and the quantity of RAM soldered on.  parts-people.com is a good place to check.

The boards run between $160 and over $500 -- the low end for an i3/4G and the high end for an i7/16G.  

What are the causes of this issue, it happens like that with no reason?!

how the device is performing very well while it has this issue? and how the diagnosis result on dell.com is with no error while it's different on the epsa?

Do you know if there is any other solution to solve it other than changing the mainboard?

Could be anything from a memory chip going bad (they do fail, though it's not common), to a weak solder joint holding the module to the board.  The fact that you're seeing an unrecoverable cascade of errors and intermittent faults points toward what's likely one bad memory chip.

It may or may not be possible to have a bad chip replaced, assuming a shop can diagnose which one is bad.  Since that takes time, along with the need to remove the board and perform skilled SMT desoldering and soldering, you're likely to find the price of a chip replacement on par with if not more expensive than simply replacing the board.

Unfortunately, as more and more components (the CPU, RAM and now with some systems, the SSD as well) come soldered to the board, repairs range from impossible in some cases to prohibitively expensive in others.

Why the memory test from Dell's diagnosis is passed and does not show any error?

See above.  You showed that the memory has failed the diagnostic before, and that the issue isn't constant, but rather intermittent.

The explanation is that you have a memory chip that is failing, perhaps under thermal cycling - - either when it's hot, or before it heats up.  That's not uncommon with a failing IC.

The 1st diagnostic is from epsa and its always showing the error promptly once I run a memory test (Whether the device become hot or not)

The same is to the second screenshot when I always run the test from Dell website and increasing my usage with other different applications to stress the performance with all at once " memory usage, and CPU utilization to the max" I do not see constantly with different test result any failures!

thank you so much for an out of the box solution to a similar problem.