EVGA has a support section that lists CPU and RAM support for all their available boards, just scroll down until you find SR-2's chipset which is "Intel 5520".  
 
In short, any LGA1366 Xeon from the 5500 or 5600 series and on EVGA's list in the link above will work with SR-2.  Their list is what they tested to ensure operation and thus support, anything not (because Intel made many more Xeon 5500/5600 processors) is just not guaranteed; so while Intel also made the chipset and those others will work, it is your call.  The idea is simple: Should anything happen to the board (i.e. damage) from running CPUs EVGA hasn't already tested, EVGA tech support cannot guarantee the problem was due to their board.  You effectively loose warranty if you stray away from the list.  EVGA can't test everything, they only test which processors their intended SR-2 target customer are most likely to pick.