Can 16gb ram be added with preinstalled 4gb to get 20gb RAM?

[Har17]

I bought a HP Probook 450 G6 recently and it comes with 4GB DDR4 RAM. I plan to add a 16GB stick in the other channel and I am aware the board supports a maximum memory of 32GB RAM.

I did some research on having different RAM sizes and I found out that Intel's FLEX MEMORY feature allows different memory sizes to be installed such that in a case like this 4GB on channel A and 4 GB on channel B runs in dual-channel mode while the other 12GB from channel B works in single-channel mode.

I would like to know if there are any issues that may be encountered with this setup. Kindly share your experience.

I don't want to add 2*8GB as this would require me to get rid of the 4GB unnecessarily. Besides, if I want to upgrade later, I would have to get rid of atleast one of the 8GB sticks. I also don't want to add 2*16GB now due to cost constraints. 

[Huffer · Accepted solution]

Yes no problem. As to whether it will run in dual channel that I cannot guarantee but I am seeing more current laptops able to run memory in dual channel with one module or mismatched modules. At the speed of today's processors and memory it really only makes a very tiny difference whether its dual or single channel. This is easy access customer upgradeable memory.

Service Manual 

See pp. 38-40

Its DDR4-2400 SO-DIMM. 

Post back with any other questions and please accept as solution if this is the info you needed.