There are 2 RAM sticks of 4 and one of 8?

Question

RAM

2 dice of 4 GB of RAM were inserted into the PC, I bought one for 8 and replaced one of the two dice with it, the question is - how do they work? does it make sense to insert 2 by 4 and one by 8 at the same time? How can I check if they are working or not?

Answer 1

How can I check if they are working or not?

Run a memory integrity test. If it starts, then it probably already works.

does it make sense to insert 2 by 4 and one by 8 at the same time?

There's a meaning. Will be 16GB instead of 12

Answer 2

It makes sense to put everything if there are enough ports.
Simply, if there is a difference in frequency, for example, 2 to 4 work at 1333, and the new 1600 = everyone will work at the lower nominal frequency, i.e. at 1333.

Answer 3

You should also look at the timings of different bars. If the timings are very different, it becomes possible to periodically leave the system in a BSOD, especially under heavy loads.