Thanks to all, problem solved. Flashed BIOS with version A17 and memory status become OK. System boot ok, all 16GBs are visible.  
Hello! im trying tu upgrade my Vostro 15 RAM Upgrade to 16GB (8+8) S/N:  Product Support page: Datasheet:  [URL] i purchased the 2 pieces of : DDR3L 1600 CL11 от Kingston 1.35VModel: PSD38G1600L2S From datasheet: Memory connector two internally accessible DDR3L connectorMemory capacity 2 GB, 4 GB, and 8 GBMemory speed 1600 MHzMinimum memory 2 GBMaximum memory 16 GB But my Laptop constantly Beeps after powering on and no BOOT. If i placing original Micron DDR3L CL11 4GB module - it boots ok. PSD38G1600L2S have  the same 1600Mhz and voltage 1.35v Where is the problem? thanks!    
Vostro 3558 RAM Upgrade to 16GB