dell r720 192GB memory for 1 cpu 1333mhz

1600 DIMM's will work, but with all slots populated, the memory will run at 1066.  DIMM's cannot be quad-rank.

There is nothing in the BIOS release notes regarding that ... where did you hear that?  There are also no "update" docs in the manuals folder.  Undocumented changes do occur, but it isn't common.

http://ftp.dell.com/FOLDER00500594M/1/R720-010206BIOS.txt

Thanks , dims are dual rank...

i heard that with the latest bios update i can run all 12 dimms with 1333mhz , is that true?

if there is no option i will go down to 1066...does anybody can tell if i feel any difference when i running about 30 vm on esxi 5?

Verified this works on a 720 non XD and 620R

Hi I am running dual R720XD servers with 24x16gb 16000mhz ram.

The memory has always run at 1066mhz when I updated to the latest bios 1.6 the ram reconfigured itself and is now running at 1333mhz.

This is not a Bios misread either as I have noted a slight performance bump on my larger VM's that use 32-64gb

This is documented in the release notes for 1.6, but was not at the time this thread was originally authored, when BIOS version 1.2 was the latest:

http://ftp.dell.com/FOLDER01348966M/1/R720-010600BIOS.txt