Memory speeed is determined by the Processor QPI links and the memory population rules.
E5520 only supports 800Mhz and 1066 Mhz operation http://ark.intel.com/products/40200?wapkw=e5520
9 DIMMS is kind of a strange number to be populated.
Each processor memory is independent with a max of 6 DIMMS per processor.
On a E55xx processor, more than 1 DIMM per channal (blue slots only) will cause the memory to clock down Check the Users Guide pg 47
http://download.intel.com/support/motherboards/server/mfs5520vi/sb/mfs5520vi_user_guide1.pdf Pg 47
I don't see VI in the memory configuration tool, but WB is simular http://imct.intel.com/cfgview.aspx?id=546931