It doen't look good at all man, you defenetly need at least 24Gig of ram, 32 will defenetly be better since there is more room for other program and SO itself.
If you have oonly 2 stick and have a couple of slot free you can easily add a couple of 2x8 RAM bank, it doesn't matter if the producer is different, but it nedd to be the same speed (or faster, but then you need to check if your MB support it), if you can install the same exact RAM model will be even better.
You can read the model number form the stick iteself or retrive it by Poweshell command:
PowerShell: Getting RAM Info by manufacturer, speed, serial number, capacity, DUAL-Channel …
If the memory is to be upgraded, then you have to find out whether the new memory is compatible. And you have to find out the type of your currently installed memory. The device manager does not pr…
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Don't get scared from the command like thing, as long as you stick to the Get-something command you can't do damage, so just run:
Get-WmiObject Win32_BaseBoard
and take notice of the PRODUCT value, that is what you need to search.