Default RAM for Inspiron 3953 with discrete graphics card Nvidia GeForce MX230. 2666MHz or 3200MHz???

Few years ago i bought a Dell Inspiron 3593 direct from Dell Website which came with discrete graphics card Nvidia GeForce MX230.  But the RAM they provided is 2666MHz but their website showed 3200MHz (only for computers shipped with discrete graphics card) which the one i purchased is with Nvidia GeForce MX230.  I did not do the double check with Dell Website due i trusted Dell products and services at thier Sales Website.

https://www.dell.com/support/manuals/en-my/inspiron-15-3593-laptop/inspiron-3593-setup-and-specifications/memory?guid=guid-f07064b8-2eb4-49ec-88a8-43b102e42417&lang=en-us

Happened i only found out this when I wanted to upgrade my RAM recently.  I am wondering is there any other users laptop came with same spec with mine happened same???

Now I am still waiting Dell Support to reply my question after being passing around form department to department.  Hope to get an answer from Dell what really happen to this.