Hello Khushed   BIOS update 1.4.8 added support for 1600MHz at 1.35 volt: [URL]   Yes, you can. No, you should not change any BIOS settings. If you mix 1.5 and 1.35 volt DIMMs it will run all DIMMs at 1.5.   Yes, all memory will operate at the highest common voltage of 1.5.   This is not an issue since 1600MHz is now supported at 1.35v, but yes it does support 16GB dual rank at 1.5v. Yes, all 1.35v DIMMs can operate at 1.5v. Thanks
Hi! I have r720xd server with 2xE5-2630v2 processors 2x8GB RDIMM 1600mhz single rank 1,35v memory blocks are initially installed on my system. exact line from configuration is :  Bios memory settings are 1,35 voltage. From online documentation I have learned that R720/R720xd can run 1600 mhz memory only on 1,5 voltage [URL] Now I need to upgrade system to 64GB memory. Option is to buy 4x16GB 1,5v 1600mhz dual rank memory (available in my country), or 4x16GB 1,35v 1600mhz dual rank memory (not available or hard to purchase) . questions are: 0. Can I use 1,5v RDIMM 1600mhz memory in my system. Should I change 1,35v voltage bios settings and how I can do it. 1. Can I use 8GB single rank memory modules with 16gb dual rank modules at 1,35v together 2. Can I use 8GB single rank 1,35 memory modules with 16gb dual rank modules at 1,5v together  3. Does my server support 16gb dual rank modules at 1,5v (if i decide not to use 2x8GB old memory at all) and should i use only 1,5v modules for 1600 speed, or 1,35v module will work at 1,5v 1600mhz? Khurshed
PowerEdge R720XD Memory upgrage