I have problem with Radeon RX 560 Pulse 4GB. There was burned a fuse (pci express with letter R). I have checked short circuit using with multimeter but there wasn't "beeping". Moreover I tried check it again using power supply (1V and 4A) but nothing goes hot.

The graphic card work (computer start). I have tested it in furmark and in 3dmark. Futhermore i teseted it in cryptomining (there was about 8mh/s for eth, this card have about 10mh/s). That was very strange for me so I have checked how many memory is use in GPU_Z. There is only 3GB.

I feel that one of memory chip is broken but I would to be sure. I can't find the same chip in the stock. The memory is Micron RT8880C.

So there is my question:
Is the memory chip is broken?
Is there are any method to veryfy which memory is broken?
What it can be if not memory chip and how can I do to check it?

I made some photos

Windows 7 have a bug with some radeon cards/drivers. Try reinstall win 7 or install win 10.

I have got a windows 10 already. GPU-Z shows that graphic card has got 4gb memory but after run for example mining GPU-z show that 3GB is used only. It is problem with graphics cart but I wonder if it could be the fault of the memory controller (if not memory chip).

Try flash bios and reinstall os, looks like software errors.