Laptop RAM Upgrade - 4 GB soldered + one empty slot

This generally means placing one stick of RAM in slot two and the second stick in slot four You can potentially use the first and third slots as well

: 2 ram slot motherboard FRONTECH H61 Chipset Motherboard with 2xDDR3 RAM Slots LGA1155 Supports i3i5i7Pentium Processors 6+4 USB Ports

rambo slot wallet BTW your board supports dual channel only in 2-4 and 1-2-3-4 slots according to the manual With different sticks, like that 8GB and 4GB you've

ram not detected in slot 2 1 Test RAM with Windows Memory Diagnostic Tool · 2 Switch RAM cards · 3 Replace faulty RAM card · 4 Consult an expert for motherboard