so this SKhynix 16GB 2Rx8 PC4 - 2666v-Re2-12 is really from dell? and also since the store where we bought the server cannot give us this module again.. they offer us this "Kingston KTD-PE426D8/16G Memory" can this module work together with Kinston KTD?
Below are the part number of 2666 MHZ 16GB memory supported by T640 (I assume you have T640 please clarify if model is not correct as your first post does not have the exact model). You can also refer below link for more details on memory configuration for T640.
Non Dell memory are not supported on PowerEdge Servers. Not supported does not mean it will not work we can not guarantee that it will work as it is not validated.