It will be, even if you fake the CPU ID (to CPU with SSE4) that at the first use of SSE4 cpu code ( it doenst have!) , the CPU panic.
Your cpu end with SSE3.
But i think you can change your Clovertown XEON to an used Hapertown (also 4 Cores, SSE4.1) or Wolfdale-DP ( 2 Cores, SSE4.1) . Both use the 771 cpu socket.