DDR3 RAM IC selection

[VEGETA]

Hello

I am working on a design that has a big ASIC which is the main design chip, it requires the use of 4 DDR3 RAM ICs that have speed of 1600 MHz, each one capacity is 4 Gbit, and organization is 256M X 16. It has to be exactly this.

The reference design provided  by that ASIC uses MT41K256M16TW-107 by Micron which is faster than 1600 but its datasheet says higher speed ones are directly compatible with slower ones. The ref design has EM6GE16EWXD-12H (by Etron) as an official replacement IC.

I checked Etron's website but couldn't find that part number but rather found this: EM6HE16EWAKG-12H (the -12H doesn't exist on digikey and similar ones, the -10 one does).

The original MT41K256M16TW-107 is very pricey at +15$ each, so I would need like 60$ per one unit which is crazy. I searched for alternatives and found these:

D2516ECMDXGJD by Kingston -> doesn't seem to be available easily or at all except digikey "marketplace" (dunno what is this marketplace thing) for ~7$. Don't know about it if it is directly compatible or not.

IS43TR16256B-125KBL -> roughly 9-9.5$ on Digikey, a lot better than original one but still I aim for cheaper.

EM6HE16EWAKG-12H -> I found this one here for a crazy price of <0.35$ per unit but at 1900 quantity! I don't know if this is legit or not.

EM6HE16EWAKG-10H -> similar to above one but faster (dunno if it is compatible with slower ones like Micron part), 10.5$ on digikey but not so available.

Therefore, I ask your help in searching for a compatible, available, and cheap part to be exactly as I mentioned above. I don't care about brand or package as long as it works as the Micron part @ 1600 speed or even if it is faster but compatible with slower operation.

Thanks

[VEGETA]

no one is interested? I thought many would help. will wait and see.