Hello guys i have gtx titan with artifacts i ran mods and at A0 i have errors written, i removed second memory from down right side (this at photo) and the same memory on the other side of backplate (there is 24 memory, on both sides), and again, the same result after change memory from other card, so what im doing wrong?

Almost all similar problems on this generation cards caused by GPU failure. Try to remove that two memory chips again and measure data lines resistance. If it will be a problem there, main chip reballing may help for a while.

Ok, thank you i desoldered main chip, now i'm waiting for new stencil for GK110, btw how to check resistance in data lines under memory chip? i searched on forum but didnt find it.

Look for datasheet for your memory type, GDDR5 in your case. Example
You need to measure resistanse of all data and address contacts on board when your problem memory modules desoldered. All resistanses should be +- the same.
Data lines go to the GPU directly, so it will be much easier when it is in place

You mean resistance between ground and data/addresses lines? if yes, i will try after reballing.

Yeah, that's right.
In other hand, you can measure it one by one at desoldered GPU, but i believe that doing this on board is much simplier.

Ok, now understand, thank you very much i will give feedback when i will done reball and check resistances :)

You're welcome

After reballing GPU artifacts Has gone, mats passed ( and it was my test of reballing low temp solder paste 138degree, it was so easy, personally i prefer paste than balls 100 times more), now im stress testing and we well see, which program do you use to stress GPU memory and GPU?

Furmark for GPU and VRM testing, OCCT, Kombustor and 3DMark for memory. Some games may be added for sure.

unfortunately the same issue i replaced with other memory in the same bank A0 and still the same issue, i think gpu is dead :( i checked also data/adresses and a few was missing

No luck in this case