CPU and Memory wont be an effect with the H700 controller as the cache on the controller will be independent of the cpu and mem during normal operations. Only when there is some array/ volume issue where the resources will be used more if there are volume issues due to some raid controller problems.

If your using the iSCSI then enable the Write Back option, this will use some of the memory for performance with your controller. After that will be the amount of data from your initiators, so if you have 50 servers connecting to the DSS targets you might want to look into 10GbE NICs (Intel for example).