Soldered RAM doesn't really help much with latency; most of the DRAM latency ocurrs within the chip itself. Where soldering RAM does help is with reaching highe

Soldered RAM doesn't really help much with latency; most of the DRAM latency ocurrs within the chip itself. Where soldering RAM does help is with reaching higher clock speeds with lower power (in phones and laptops), or with reaching clock speeds that are impossible to shove through a DIMM connector (GPUs). That higher frequency helps phones save on pin count by using a narrow memory bus, and allows laptops to have lots of memory bandwidth to feed the integrated graphics when using typical laptop/desktop bus widths.