i want to upgrade my imac 2017 4k ram

[giotarakji]

hello every one
please anyone can help me
im looking for memory to my imac 2017 4k

the brand is ( Crucial )

but there is 2 type of the ram
both is 2400 and ddr4

but there is something called dual rank or single rank
i dont know what the different between them

so should i choose ??

please help me guys im so confused

 

[giotarakji]

hello every one
please anyone can help me
im looking for memory to my imac 2017 4k

the brand is ( Crucial )

but there is 2 type of the ram
both is 2400 and ddr4

but there is something called dual rank or single rank
i dont know what the different between them

so should i choose ??

please help me guys im so confused

and is the Timetec is a good brand ?