Hello Mike I wouldn't say it is recommended, but it will work. The only problem with mixing memory is that you will not be able to populate the third channel. It will make slots A3,A6 - B3,B6 unusable. I would populate it something like this: 8GB - A1,A2,B1,B2 4GB - A4,A5,B4,B5 I can't think of a way off the top of my head to hit 40GB. If you are only running a single proc then you would populate it like this: 8GB - A1,A2 4GB - A4,A5 If there are any questions let me know. Thanks
Does anyone know if it is recommended to mix the sizes of memory dimms on R610s?    I have a pair of R610s and a hand full of 4GB and 8GB dimms that I would like to spread evenly between the 2 to give them each 40GB.
Poweredge R610 Mixed Memory